SBC Water Pump Bypass? (Read Description for instructions) Vortec heads vs Traditional heads 

For all us old guys that didn't have vortec heads back when, thank you I really wish you guys were on the west coast Take care

Thank You Thank You Thank You. So glad I subscribed and learned this very important coolant issue. I'm installing 059 Vortec heads on my 1985 Gen 1 SBC. I had no clue this was a thing. Drilling holes in the thermostat is a great work around.

So I have a 1985 Chevy C10 with a 262 v6 that I swapped to a 350 that I built. Its cammed and has Summit Racing Vortec heads. The block and accesorries were from a 1997 tahoe. Kept the accessory brackets and accessories but I got rid of the Vortec injection and put an Edelbrock intake and carburetor on it. I wish I would have watched this video when I was setting up my heater core and cooling system. I kept getting air trapped. I later figured out about the thermostat bypass. Great video!

Great info that I've never heard anyone talk about.

Omg. Thanks man. I'm swapping my o school tomorrow to vortec heads. After all your vortec videos I decided to do so. Thanks for all your time and info !!!!

Jesus man Thank you. Explained everything very well and solved my overheating problem. Thanks for the help

i drill 2 1/8 holes in all my old small block thermostat since the 70's.. this trick also helps in case you stat sticks closed, not a cure.. but helps water flow and again case your stat sticks closed you have a lil some thing to get you to where can replace it.

Thanks for the info, swapping vortec heads on my mercruiser 5.7.

I've been drilling the t-stat on my atvs, really helps. Great video.

Nice tip! Lots of people don’t think about it.

Excellent video! I did not anything about that. I just don't know what I don't know. Thanks for the enlightenment.

Thank you for this video. I've been fighting an air pocket on my vortec head 880 block all summer. Watched this earlier today and drilled my thermostat and bingo it's gone. I drilled 4 5/32 holes I live in Michigan so won't be driving this winter. Much thanks too ya. You gotta new sub here😀

Steve from Annapolis all these years I've been lucky never had that problem never thought about that good job thank you so much

I just learned something new, THANKS!

Great info in the video! No one talks about the coolant bypass on the vortec’s. I’m certain this should fix the problem I’m having!

Awesome video Pat. Just finished my 383 build and didn't want to run vortec style water pump. I will drill 6 holes in thermostat and eliminate bypass hose. Thanks for the video!!

Can I like this video 100 times?

Interesting point , I thought about that once or twice I have had no problems so far , but then again I drill a small hole in most every one ! You only need one. Some of the newest cars have a piddle in thermo, that does the same thing ...it will also help a customer's if they have to add coolant it adds a constant bleed feature that aids a on the fly refill for the nongearheads that don't know much about cars . !

Great video! Super helpful!

I have a 77 GMC K25 with a 400 SBC that is prone to air pockets in the coolant, I will definitely be drilling some holes in the thermostat.

Thank you for teaching me about this mystery I have wondered about for three years! What I found online was how I would ruin my new engine if I didn’t plumb the manifold to the water pump. What I came up with was a silly looking copper pipe looped around! I learned about this thermostat technology in my Toyota class in 1988. It was called a “jiggle valve” and is such a primitive genius idea. I will make the modification you have outlined and use my existing bypass hose plumbing for my new propane fuel system.

Thank You

Great info!! Thanks.

I was just dealing with this. I have a 1979 block 383 stroker with the water pump bypass that I’m swapping into my 02 blazer. I’m using the 4.3 belt set up and needed a reverse rotation water pump but it doesn’t have the bypass. Now I’m confident that I can plug the block and use a bypass in my performer RPM intake 7101. I have the mid 90’s production World Products S/R Torquer heads. I’m assuming I don’t need to worry that they are not going to have the pump bypass anymore on the block. Awesome video. Thank you.

Good info 👌👊

I always drill 1 head for it, and put that head on the passenger side. This really is an overlooked item, and guys never really understand what im saying when I bring it up. I only drill the 1 side so the heads can be swapped to block it back off IF the motor goes back into a Vortec truck in the future.

Hi I can across your video the other day. Last year I put a new water pump on my 77 350 sbc in my 39 chevy . It did not have the bypass hole on the water pump . Well I had a air bubble. Today I put in a new thermostat 180 temp . I drilled 6 5/32 in the new one . I drove it 26 miles and new got over 140 degrees. It was mid 40's here today in Kansas.

I'm loving your channel I have a big block 427 60 over so it's a 440 howards hydraulic roller cam afr265 oval port full cnc heads victor jr.intake 850 Holly hp carb my cam specs 235x242@50 618 lift on a 108 lsa it's a lil over 10 to 1 compression I was hoping for 550 hp or at least 525 but I think I'm a lil shy on duration Monday I suppose to go pick up a 358 small block that has a steel crank pink rods and a set of 67 corvette dubble hump heads with 202 x160 valves the guy claims the motor makes 450 hp . So if I do get it I might be interested in you working a pair of afr as cast 195 heads. Can't wait to see the people's build over your build complete oh by the way the 358 I was talking about only has like 512 lift flat tappet lunati hydraulic.

You have got a really great channel here my friend. Keep up the good work.

Thank you. I learnt something today! Never had issues with my Vortec heads on old school block heat wise but I might drill some holes in my thermostat anyways.

I drill a couple small holes in the thermostat so the water still flows a little. And I'll put a brake bleeder in one of the intake water ports near the thermostat housing

If you are running a htr core it also acts as a bypass unless you have a water shutoff valve for temp control.

Well done video, great information. Noticed the serpentine setup. Maybe do a video on how you changed things. This is a repeat comment, the original dissapeared.

Just an FYI. I have only ever put a single 1/8" hole in the thermostat flange, to purge out any trapped air, and I have never had a hot spot problem. Personally, I think you are putting in too many holes, and too big of holes. Anyway. I like your content, you just got another sub.

I usually drilled a 1/16" hole my t stats. I was trying not to affect it too much. It seemed to work.

My brother bought a Motown block and was having trouble leaking water from the water pump because he used an old-school water pump in the block did not meet up to the water pump plus it did not even have a hole in it for the water to flow through so we took the old school water pump threaded and blocked let Bypass in it but if he ever gets rid of the engine somebody else may have trouble leaking water from there if they change the water pump

I just subscribed to your channel and in the past I've watched a ton of videos on the vortec heads and am looking to get my hands on a set of 062 set .. my question is I'm in Canada just across from Detroit.mi .. how much would you charge me to do a set for me with everything you've learned that will make the most power out of them .. ???? I did watch your video were you said that there wasn't much difference between 2.02 and 1.94 on the intake but you did say that there was a significant difference on the exhaust between 1.50 and 1.60 and should go with the bigger exhaust valve ... I'd be looking to put these my stock 350 and of course I'll be upgrading the cam and lifters as well as timing chain oil pump and water pump but at 5th same time I'm looking to retain my TBI setup .. now GM does make an intake to bolt to vortec heads with the TBI setup on top .. a bit expensive intake so I'm looking for another manufacturer that also makes the same intake style but definitely cheaper in cost .. you're input would be so much appreciated and thank you in advance .. you're Canadian neighbor

Great video. What if I’m running an 880 block with no bypass holes and also running aftermarket aluminum heads that’s not drilled for a vortec style intake ?

Just a thought if the holes in thermostat stop thermostat from opening motor could run too cool and circulation is slowed down cause thermostat is not opening as much. Even just two holes in thermostat can cause it to not open as much as it should.

Usually just drill one 1/8th inch hole in the thermostat, some already have one.

Is there anything look for when buying late model 880 block

Thanks!

Little late to the party here but, I’ve been blowing water pump gaskets by, what I think, is higher rpm before the thermostat is open. I’d like to install the bypass hose from the manifold to the water pump but not sure which hose to cut a tee into..

Ok, so @ 3:32 I got just a tiny bit confused? I have the old school block with pump bypass, and about to put my Vortec heads on (followed your every step to build them!), and not sure if I need to do anything or not? You said something about “you guys won’t have issues”, but wasn’t completely clear? Am I good, or do I need to drill the T-stat? Thanks in advance, Pat!!!! I love every one of your vids!! You’re awesome!!!

Great video series, my current build uses 062's. my question is what head gaskets do you use, watching this video i notice you using what looks to be valve pocketed gaskets. I've only been able to find two types of vortec head gaskets, Cometic MLS Head Gaskets C5269-023 (.023) and Cometic MLS Head Gaskets C5269-027 (.027). have you found any more choices ?

If you see this and answer I would be so grateful . I have a later block with the bypass. I’m using vortec heads that block the bypass. And I’m using a v belt direction water pump . From what I gather from this video . I can also just drill holes in my thermostat and be ok also right ? Thanks in advance . Awsome video

only ever drill a 1/8 hole in a thermostat as a air bleed . The factory only bypasses the coolant to one side only. Far better off using a bypass hose ( like a big block) . this stops the block & heads going into thermal shock as the thermostat constantly opens and closes. A thermostat is considered open at 8mm open and flowing its max.

Hey Pat, have you heard or know of any difference in the TBI block water pumps with internal bypass and the later vortec pumps with external bypass having any difference in heights for pulley alignment? Also if the pulleys themselves have different bolt patterns? Reason asking is I have a TBI 355 I rebuilt recently with refreshed 193 heads. But also have a set of 062's that I want to swap and do a carb conversion. My truck still runs like a slow turd and been having TBI issues. I've replaced every sensor, pigtail connector, vacuum lines, checked vacuum leaks, rebuilt TBI etc. I'm fed up with the TBI system. So what I'm hoping is to plug my internal bypass on the block, run a vortec water pump with external bypass going to my air gap 4150 flange intake I have to go with my vortec heads. But can't find useful information about the two difference for possible pulley alignment problems. Thanks in advance. Really appreciate your videos

I have a vortec block without the coolant bypass hole and I plan on using after market heads. So instead of using the ugly vortec water pump and the bypass hose to the intake I can just drill holes in the thermostat? Thank you for this video you have a new subscriber!

I am using a blueprint engine setup with the vortec style heads and the block doesn't have the bypass hole in it for the old style water pump that is going on it I am going to drill some holes in the thermostat after seeing your video on it so I don't have to run the hose from the water pump to the intake thanks for the information. But do I need to block off the bypass port on the water pump itself and what would be the best way to do this ?

At 4:25 you point out a port on the intake manifold for running water bypass. I have that same intake (2716) and run 906's and I have my radiator thermostat in that hole and the one just above it (top right) as my bypass. My SBC 350 never gets above 200 degrees. Even at long idle like drive in. Q: can you use either intake hole for a water bypass running vortec heads?

Thanks for all your info. If i was to drill both vortec heads left and right would I need to drill my thermostat. I have a old block 73

What if I use a heater core back into my passenger side of my intake manifold will that work as a bypass my l31 does not have the 3rd by pass hole for the left side of the water pump but my water pump has that hole

I am retrofitting an 02 4.3 V6 back to carburetor and HEI distributor. My intake manifold is an Edelbrock Performer, which does not have the port for the bypass. Can I just block the water pump bypass and drill the holes in the thermostat and be done with it? I could put an elbow up on top of the manifold and fabricate a bypass that way, but would rather not. Thanks for your help.

Can I run old school heads on a no bypass block and put an external bypass from under the thermostat to a tee in the heater hose at the pump

Hey bI've been doing that on all my cars bypass or not !

One more quest. So if I drill my 880 block where the extra wp hole is. I know it is not all the way through. Anyway if I drill it will I only need to drill one head deck surface on my 906 heads. Or do I need to drill both head deck surfaces.

Has anyone tapped the bypass hole and plugged it off??????

Good thermostat already have air bleed hole with small valve in it to block coolant flow )

I am also running a third gen trans am with a T-76 I'm looking for a good set of turbo manifolds are those the CX racing single turbo headers they look like they won't interfere with my air conditioning but the crossover pipe might

Hey Pat, why not just drill the bypass hole into the vortec head, I have both the block and water pump with the bypass. I have put a hole in the T stat for a long time to deal with the air issue.

Great video. I have a SBC 350 Gen 1. I have plugged the intake and water pump bypass hose so there's no hose there. After seeing your video, i think i should put the bypass hose back from water pump to intake. Or can i just leave the outlets plugged but drill some holes in the thermostat.? Its either one or both, correct? I live in a very hot tropical country by the way. Cheers

Would I need to do a bypass or just drill the thermostat like you said, my block is 85 vette 14010207, vortec heads off 96-98 truck, edelbrock performer intake 7116, front accessories waterpump setup from 89 truck, 383 cubes, thanks fire the video

This is really interesting. I have an 880 4 bolt block that has the bypass, the timing cover holes are drilled and tapped and it is also drilled for a mechanical fuel pump. A bit of a odd duck but perfect for my plans. Building it to replace a cracked block engine in an 1987 21' SeaRay boat.

hey brotha love your videos I have 880 block that does have 3rd hole on block so your saying if I use older water pump with vortec heads all i need is holes in tstat i dont need to run hose from water pump to intake doesn't that do same i live AZ so would it be good to do both

Can stock vortecs work on a 400Sbc + 040 bore. Stock pistons, comp came up fitted 9.2:1

What about older style heads with the bypass on a vortec block without the bypass? Drill holes in the thermostat to solve the problem?

Any recommendations on where to get after market vortec heads new? Also any experience with the eBay sbc aluminum heads?

Figured it out if I use my heater core running from my old school pump to my heater core from my core to my intake manifold I have a l31 block and vortec heads will I be good without even drilling into the t stat ?

hers the deal , i ordered a 350 crate engine 4 years ago , checked the block when i got it , 5.7 , i ran the code 96/99, but they put 305 mismatched heads on it , anyway its been on the stand for 4 years wrapped in plastic , they have changed the entire engine back to flat tappet , so im getting ready to change it back to a roller engine , vortec heads , rollers , cam , you know all that , i just went down in my shop and looked at my block and water pump , both have the 3rd hole in it , so when i get theses vortec heads ,,, is all i have to do is have the hole drilled in the head so the water can go through the pump into the block and into the head and thats it ? , or what else needs done ? i have the provision for the fuel pump , but im going to change the cam good lord willing back to the same spec cam it had , but what cam do i use that has the same vortec specs but with a fuel lobe on the cam , mainly just let me know what to do about this cooling system issue , if im following you right , all i have to do is have the water hole drilled in the head so the water can flow from the pump through the block up into the head ? is that correct ? and do i need to have both heads drilled or just the one , thank you very much , and by the way i called ATK VEGE where the engine came from and they more or less said im beat , your warranty ran out a year ago and thats it , regardless whether the engine was ever installed or not , thank you very much for any information you can give me .

So wether I got it or not it would be great to add no more than 4 holes if I’m following you right

So what do you use to plug the hole with

So if I have vortec heads on the engine I don’t need to worry about the bypass hole in the block? I can run a tbi pump on the engine to keep the reverse rotation? (vortec 880 block with the hole below the water pump bolt + mechanical fuel pump machined)

Ok.. So if I have a 1st gen block that HAS the bypass hole in the block and I want to use the vortec heads with the intake manifold bypass, which water pump do I need? Do I have to plug the bypass hole in the block in order to use a water pump that has the intake manifold bypass hose provision? Sorry If I seem obtuse ..

Will the water flowing through the heater core back to the radiator do about the same thing? I have a set of 906s oh my 93 C10 TBI motor., 5.7?

Can i run a conventional normal rotation water pump on a vortec block with vortec heads. Putting in a 79 squarebody work truck and it has hydroboost and dont want to convert to serpintine set up.

Should I drill the bypass hole on my vortec heads?

Question I have a buddy with a 305 in his 87 monte carlo. He wants to put some 906 heads and vortec intake and carb and distributor. Will he run into any issues with the vortec heads on a 305?

If the pump bypass puts water in the passenger side head and the thermostat is closed there is no where for the water to return to. Water has to flow through the thermostat and into the radiator then back to the pump. If the thermostat is closed no flow.

Hey, thanks for the video. It really helped a lot. I'm falling into the catagory of tapping and plugging the bypass hole, so I was hoping to ask a quet. I'm using a vortec water pump on an older sbc TBI (project). So I can just plug the bypass hole there, drill 5/32 holes on the thermostat but am confused what to do with the two connections on the vortec pump. Which one is bypass, and which is heater core? Thanks for your time!

So If I’ve got a stock vortec with the 062 heads, it would be recommended to drill the holes in the thermostat to keep the heads cool? I’ve heard they’re prone to crack

I have an 86' block. 1 piece rear main, BUT flat tappet cam. Non roller. It has the lower water pump bypass hole in the front of the block. But it always does overheat on first startup. I never could figure it out. Engine suffix code is DDL. Im wondering if the deck isnt drilled for the bypass. ? Its also factory machined for mech fuel pump and all the timing bolt holes. Its an odd duck.

Only have 2 outlets on the water pump, large to radiator plug the small 5/8 to the heater, have the bypass in the front of manfold. Just wondering how I can run this 2 the water pump. Thanks

what about running a tbi serpentine setup and water pump with vortec heads.....?? mine had never run over 180?

Can I use a short Chevy water pump on my 383 Vortex build? All of my accessory drive pulleys are for a short pump. Thanks.

I built a 350 SBC out of a 99 Tahoe. Both heads cracked as per usual. I replaced them with aftermarket AL. Heads, and now I am finding out about the BY-Pass hole. I assumed it was plugged from the factory, like the fuel pump. Yes, we all know what happens when you ass-u-me. I am going to attempt to drill and tap in the car. What is the plug/drill size? Or is there a brass plug I can knock in?

I put new Vortec heads on my 74 sbc. Decided to drill 2 1/8 holes in the thermostat instead of drilling the head. Having trouble with the system pressurizing, top hose gets hard as a rock while it’s running. Doesn’t overheat though, ran it today and it stayed around 180-200. Any suggestions??

I have a 880 block without the coolant bypass the extra hole on the passenger side but my old school water pump has the extra hole I’m going to drill the hole what should I do from there

What does the bypass do exactly? Do I need it?

What did you use to plug the water pump bypass hole

What if I have the bypass and drill 5 holes? I was told to drill 5 holes by my buddy before I seen this video lol I’m also in Texas tho

This was my 3rd vid and 15 seconds in I realized I'm not subbed.... 👉subbed

Are you a Canadian Business?

I take those dart iron eagles off ur hands lol

I drill a hole in every 1 I put in these old engines

Oldsmobiles have a 5/8 bypass!

Why not just eliminate the Thermostat ?

Horrible advice. U cut that many large holes into your thermostat u mine as well take it out. Your not letting the coolant stay in long enough.

@PISS-CUTTER Performance Just got my 906s from Clearwater. Just wondering how many holes and what temp stat do you recommend for driving in Phoenix during the summer ('93 TBI 350 block)