454 BBC REC PORT VS AFR OVAL-PORT HEAD TEST 

500, 600, 800, 1,000+ HP...we just throw these numbers around like nothing these days eh? Man, if you had a 400 HP street machine, you were something back in the day.

Excellent test. In the mid 90's I bought a 70 Corvette from a car lot. It had a 454 but they knew nothing about the engine. It turned out to be an LS6 straight out of a 70 Chevelle. After reading an old article by John Lingenfelter that showed a really similar gain using oval ports over rectangular ports I pulled the 088 heads, and factory LS6 aluminum intake, and built a set of 049 oval ports according to Lingenfelter's specs. 2.19/1.88 valves and some mild port work on the short side radius and a port match. This along with an Edelbrock intake and I went from 13.0's in the quarter to 12.30's. I didn't have the money to dyno it. I literally got into shouting matches several times with die hard rectangular port Chevy guys who said I was a fool. They refused to believe that oval ports would make more power. Of course I was only pushing 450 to 480 estimated horsepower. AFR heads I'm sure are much better than some worked over factory heads but I think even the factory heads would have easily supported 600hp.

I had a 509" BBC with that same cam, 10.1 compression, Edelbrock 290 Rovals, Air Gap, 1000 cfm Holley. Great street Engine, it ran 11.80s @115mph with a 3.42 gear at a 4320lbs race weight.

This test makes me proud to be an AFR fan since 1993! But we shouldn't be surprised. Big LS heads make 600-ish hp on 270 cc port volumes. Even cathedral port heads at 235 are wicked. I knew the 088 heads were toast when I saw the AFR's had 20% advantage in mid-lift flow. A cool follow-up test would be to put the iron heads back on and see how much more cam is needed to match the power of the AFR combination.

I have a pair of 088 heads on my 468 in my 57 Bel Air. I'm going to replace them with a pair of AFR 265. It's strictly a street car and I seldom twist it above 5,000 rpm. Great video.

Look at the exhaust flow numbers on the AFR's! That us going to make some huge gains especially with a power adder.

John Lingenfelter set many a record with the early 70's oval smog heads because they flowed very well. Plus oval ports are more efficient than rectangular heads. Also has something to do with surface area friction.

Great comparison. I had a 496 in my 70 Chevelle , 300CC Oval port AFR’s, Edelbrock RPM (non air gap) 248/254 Comp Solid Roller , 10.7:1 CR, 950 Holley Street HP 2” hooker headers - made 706hp @6500 rpm and 643 ft/lbs of torque. Super strong performer. Great heads. Same heads then went on a 572 cube with super victor and 270@. 50 cam and 11.8CR and it produced 807 hp and 739 footies. Now I’m building a 582 With 360cc Mamosport recto heads ..

Port velocity and low lift flow are 2 often overlooked components in a head. Your valve with a .600 lift cam only hits .600 once per event, but will be at .400 lift twice.

AFR heads rule!! Been using them on all makes of engines.

Love the BBC content. Keep up the good work!!

Can’t wait to see some testing with the AFR Enforcer heads. 👍🏻

30 years ago I was running modified early oval port heads on my 460 inch daily driver 68 Camaro and beating weekend warriors with big blocks and rect. port heads.In those days nobody ran aluminum heads on the street. They were cost prohibitive.My car was 100 percent street legal and driven to work daily.Driven and raced on treaded tires.

I've been sold on AFR heads for years now. In 2003 Hot Rod tested the 165 cc afr's on a 5.0 and made 405 hp with the stock cam. In 2004 ,Hot Rod tested a set of 195's on a 350 zz4 short block and made 520 hp at 6600 on pump gas. Super Chevy tested the 195 eliminator heads on a 383 in 2006 and made over 540 on pump.

Thank you Sir , I just happen to have a 468 sitting in my garage and was thinking about the best way to improve power levels without touching the bottom end and you just answered all of my questions 😀

I’m guessing there would also be a massive weight difference too as an added bonus.

Great results! Keep testing, I'll keep watching.

Excellent test Richard. I have been running almost an identical combo for nearly 20 years. 468, 242/248 hydraulic roller but with a different lobe that gives me .612/.638 lift, 10:1 compression. Biggest difference is AFR didn't make the oval port head back then so I run the AFR 305 rectangle ports. I also use the RPM air gap intake and 950hp carb on top of a 1" open spacer. It makes just a pinch over 600hp. Nearly identical to your test. Street driving with some dragstrip mixed in for nearly 2 decades. Very well behaved engine that has no lack of torque down low. 4108 lbs race weight on a 275 radial using a mild 3200 stall 10" converter I've gone 1.57 60 foot and very low 11's at 118 mph. I drive it everywhere. So glad you tested the intake swap. I ended up with the RPM because I didn't want to give up the torque in the range I drive the engine the most. I'd like to see more tests like this. Planning to swap these heads on the new 509 I'm doing with a little more camshaft. Might go single plane at that point. We'll see what the dyno says.

That’s a whack of power for such a (relatively) small camshaft! Awesome test!! 👍🏼

Love the channel playlist breakouts...thank you.

Excellent , Love these kind of tests. Keep them coming !

I watched this video several times a week for a long time dreaming about buying these heads. Finally pulled the trigger on them! Fully machined ports set up for my solid roller. Can’t wait to toss them on

We raced the early oval port heads back in the early to mid 1970's. Some head work and bigger valves, made these run extremely well on the street. I ran the Carter Competition Series 850cfm & 1,000cfm Thermo Quads. On a 180 degree intake manifold. Miss the early days of experimenting around with things...

Thanks for all or your work Richard!

You bring all the great content Richard keep it coming and keep growing you are the man

Oooo. Love the Playlist idea. That had to be a ton of work. Thank you 👍.

Thanx for organizing the videos by motor. The beauty of good low and mid lift numbers is that the valve is at those lifts twice during the intake or exhaust stroke, it’s only at full lift once

Thank you for creating the BBC playlist. Great content as usual. I still think you and @dynobrule should create a BBC specific channel

I have a customer at work that wants his 1968 Chevy C10 stepside with bbc hoped up a little . Thanks for the recipe.

another great video Richard . I'd like to see a similar set up with a set of profiler #174's and a Flo-tek comparison .

All the rec port guys be like "but, but, but, but." Lol. Those mid lift numbers make me wanna shrink down and put a radar gun on those air molecules. Air velocity has gotta be just crazy fast. Exhaust flow numbers nearly matching the rec port intake flow numbers? Holy wow man. 80hp peak gain with solid gains everywhere? Wow. Just wow. Do they make a Pontiac version? Asking for a friend. Lol

That’s a relatively mild cam for a big block, really good power numbers because of really good heads. Torque peak is only 1.22 lb-ft per cu in and power peak is 1.33 hp/cu in or 1.07 lb-ft. BBCs tend to make lower specific output but make it up with lots of cubes. This engine with either intake would be a blast on the street! More really good info from Richard!

I’ve been watching your channel off and on, and find it fascinating, and this head test got me thinking about what a guy told me a story about drag racing, so grain of salt, but he told me he blew up his 11:1 bottom end, so he took his cam and heads and put them on a stock 8.5:1 short block and his time slips dropped about .4 of a second. I thought compression had a lot more effect, but airflow is king is seems. Keep up the good work👍

Nice info!! That's the case when bigger is not always better. Thanks

I always loved it when people told me I couldn't get 400 wheel horsepower with vortec heads because you can't get high lift with them. Max flow at high lift is only touched once, a good head is one that flows very well throughout the entire lift range not just peak remember a .500 lift cam will spend more time at .480 than .500 so you want good flow under your peak cam lift

Awesome comparison and heads joined it very much

I’ve been saving to get those AFR’s!!!

Hell Yeah Rich back to the GM stuff is where things get Fun.. plus a big Block man it never gets old💪🏾💪🏾💪🏾💪🏻💪🏻💪🏻👀😎

Perfect combination with the AFR and the air gap

You have a ton a amazing info on how to build for every power level on every engine.. Id like to see some " how to build for ever budget" Where you do a 3K, 5K, 10K, +++ build to show the kind of power you can get on each budget.

Thank you for your videos great content

Love the playlist

It's the low to mid lift #s that matter. High flow through a small port yields higher torque across the powerband. The AFR head just smokes the factory head throughout the lift range.

This test I think, more than anything, is a comparison of the technology going into these heads. Those 088 heads are essentially the same rec port head GM has been making since 1965. It's had minor changes to the castings, mostly in the chambers, but is essentially the same head they were making in 1965. Those AFRs are 60 years of advancement in cylinder head design. The exhaust port was always the biggest weakness the factory square port heads had, they need extra exhaust duration on the cam to help them out. That's why the old 454HO crate engine had a 211/230 @ .050 cam in it.

excellent video! i run older oval big brodies raised runners on a 510 short deck in a 1971 stringray on street. torque and throttle response is like fuel injection! insane torque. even street race bikes have hard time hanging in. OVALS rule!! just had a new custom gring solid roller cam fabbed by isky. now motor dynos over 800 hp. insanity!!! best thing is i hide it all under factory big block hood with old 1080 barry grant carb. sleeper that destroys! dr thrash

That's Richard I been waiting on the infamous Rec port vs Oval port.

Wonderful test love it

That was a freaking awesome video

Thanks Richard

Velocity! I like building peanut port heads for street/strip. I always have the last laugh! 🚦 😊

Great job on the videos Richard. AFR kicked ass but they are quite expensive. I am totally impressed by the power output with such a small cam, kudos to comp cams. I wonder what would have happened if the cam was swapped for one with lift of .600 to .650 with a 244 to 248 duration?

This is so true man.....but i knew a ol wildman back years ago that ran and ol 66 chevelle 427 square port/solid cam.4-speed 4;10 with factory parts through out that ran 11;60,s give or take all day long....ol timer.....when someone would build a magizine built engine and wanted to know how it ran....you ran him....low cost....those heads on here cost more than his car and he still has it to this day.....he twist that ol big block up there in the rpm,s.....money has took over on the true hot rodders.

Awesome vid Richard !! Man, i wish AFR had an offering for Big Block Mopars.. 😕

Several years ago I help a fellow when I worked for GM as a line mechanic on his 68 Camaro that had a aluminum 427 chev power glide ect in his car. He told me back then that the oval port head that were ported by folks that knew how to make them work were a pretty impressive head. He had been talking to some guys that built motors in the Dallas area . There still there I believe . That was a long time ago but I never forgot what I was told about those head .

A lot better flow on the exhaust side as well. Thanks

From my math it went from exactly 10.00:1 to 10.64:1 which is a decent compression bump but since you were going to aluminum heads that alone won’t really do much, the 50 year newer technology of the AFR Heads is what gained all the power !!!!

Great video

569 foot pounds on 468 cubes is 1.21 foot pounds per cubic inch. Ideal is 1.3 which means there's power to be had! It wants a different intake. Ideally, a longer runner will do it, but a tunnel ram is worth a shot.

It’s a bummer the 3 thumbs down guys must have had a bad day today !

I just put together an old school 454 for an old school style street strip car 😁 10.1, iron rec. heads, .700 lift, N.O.S., and a tunnel ram. Just barely getting started on tuning, feels healthy so far. Does make me wonder how much I'm leaving on the table, but the cam, intake, and nitrous might help lessen that a bit🤔 At least I can tell myself that...

All AFR heads seem to make more power than the others

That's a great idea, Richard ! Throw all the BBC stuff in one place so it can be found quicker. Those little AFR's are THE SHIT. Science ! 👌😎👍

I went with a mild setup on this engine so I would blow up my trans while towing. Got to building vthem for extra building room later on 🤘😁🤘

Small port for the win! Just needs a 200 shot now😏

Round '95ish was following a Pontiac head porting series Limited volume max flow techniques for super stock No aftermarket heads There were few then any how. Rich I would like to see RA 4 722 heads or 71 455 HO and the 6X heads from mid 70s Look at the stock port shapes Cool stuff

I just bought my first set of AFR heads. 190 vortec for my pu

I was expecting 40-50hp. 80hp is insane!

Thanks! Much info here. Does this apply for marine BBC aswell? In marine engine, low end T is good for fuel com...

Question... Was the power/torque gain mostly from the exhaust side? I ask because the intake side showed a good up it air flow But the exhaust side was definitely a bigger gain.

You know what I'd like to see?... I'd like to see a comparison of stock iron heads, like 781's, 840's, 360's, 292's, 391's, etc.!! No port work, just a good valve job and let 'em rip!!!

The most power I could make with a 454 and factory rec port heads was 706 ,and I worked on those heads for ever

Sometime I'm going to put my new 540 engine together. Around 9.1 - 10.5 to 1 compression, iron oval Port heads, nitrous hellfire top rings, 4150 carb, hydraulic roller with around 230 at .050" 2,000 stall. My big shot adjustable plate and with my adjustable top shot nitrous in the air cleaner for 2 kits with a Max of about 575 extra ponies of nitrous fun for the street and some track. It may die with that much nitrous but you got to try. I've had great luck with nitrous over the years.

The title had me wondering why the British Broadcasting Company would be worried about 454's.

always liked the oval port heads n now i know why!!...u might want to do a little comparison n let people know u can adjust compression ratio with head gasket thickness...just a suggestion....keep up the good work

Been looking at the 265 heads but been contemplating the cheaper afr 320 enforcer heads (rec ports) that are roughly $800.00 cheaper. Our short block is similar except it has a small Howard’s solid roller with .600 lift and 237/243 duration @.050. Haven’t really seen any back to back tests with the Enforcers.

Aluminum heads can handle more compression. And need more at least a full point to compare to iron because of fast heat dissipation. AFR are truly one of the best out there.

I have something close to that combo w/ the AFR heads, but in talking with AFR and some cam guys they say those heads prefer a single duration cam. Any chance in doing a spilt vs single duration cam test on that motor?

Wonder how much gap it would of closed porting, milling and doing a good valve job on the old 088s.

Nice seeing Richards subscriber numbers climbing.

I'm KInda wondering about port shape or even chamber shape improvements or spark plug location change? ?hat also may have influence some of these results..?

how would your fav cam compare to this one in the same setup for a street bruiser? both have flat torque curves from around 3k up which is a good starting point for a street stall - curious what vizard is doing for you on those heads as well - plz let us know!! hes been my inspiration for 25 years!

What happened at .100 lift with AFR intake flow? It was lower than the rectangle iron head.

I have a pumpgas , oval port, hydraulic roller 462 that makes 570hp. Flat torque curve. Hand ported heads. 10.4/1

Big block Chevy have a bit of a handicap in port design. Cylinders 2 6 3 and 7 run leaner do to the fact that the port is angled into cylinder wall where 1 5 4. And 8 have more of a swirl into cylinder. I wonder how cid symmetrical port heads would stack up to any other head? big block pro stockers ran Pontiac symmetrical heads for this reason. There is a way to offset the leaner cylinders by running one step cooler plug in those cylinders. It’s all pretty much bench racing theory but maybe you can run some Dyno sessions on this with some exhaust temp readings? Thank you Richard for all your research on big blocks

Also with that cam what stall converter would be good for the street thanx

CFMx2@ (.78 X peak cam lift) explains what the engine should make on both combos. This formula almost tracks every time on my bench if I test with an intake manifold on the head.

Love the gen 5/6 454 tests. Is there any chance that you'll do anything with the 8.1 vortec? I've got one and would love to see some worth wile testing with different parts.

AFR heads are a no brainer, but they are not necessary to achieve those power numbers.

i will keep my high flow oval port heads for the street square port for drag racing

This 454 made more power with a smaller cam than the 454 in the oval head shootout, but this 454 used the single plane intake.

I would love to see what the power curve does at the lower speeds with a 218 or 224 @.050 cam.

Is he laughing at my 840"s and 990"s ?

don't ignore the added 80 cfm on the exhaust! Lingenfelter always said the intake makes torque, the exhaust makes HP. You could also have gone with a 1150 cfm carb on the dual plane and closed the gap with the single plane.

Would love to see a shootout between the AFR 265's and the Brodix 270 Race-Rite heads. Both are available with CNC'd chambers. I'd give the AFR's a slight advantage because of their raised exhausts. But, I bet it would be a interesting battle.

If I build a 454 like the afr motor here (500 hp in the car) will the rear end (dana 44) handle the Hp and tq in my 1985 C4 Vette? What manual trans will work good ? T56, TKO or other ? I won't be drag racing the car or speed shifting it. Normal street assault and some auto cross for fun. Also it needs to burn rubber with the posi the vette has.. Thanks for the great vids , I have watched tons of them.

I’d love to see a video with a 396 wit afr265

Here's a point a dynoed 700 horsepower blown 454 head comparison test. with an iron oval Port head in car craft a few years ago beat out the square port iron heads. The myth is the factory square Port head will be out the factory big oval port. That's not true the iron oval Port head beat the square port with more horsepower and torque across the board. And the iron oval Port head will definitely make more horsepower and torque in a smaller milder big block Chevy. Going too big in a cylinder head, carb, intake, headers will usually kill alot of torque to usually make a little more horsepower. Horsepower looks good at car shows and on paper, torque is what wins races at the drag strip.

Hi Rich--i am 65 and remember the oval VS rect. port debates back in the day. In the mid 70's i built a 67 Yenko clone Camaro and my buddy found a 427/425 with a spun rod bearing at his mach. shop so it had the rect. port heads, solid cam, 11:0 pistons, etc. I think the actual factory rated increase VS the oval heads was mainly from the bigger valves and not primarily from the bigger/rect. port heads? Did you ever see the PERFORMANCE engine rebuilding series on how he built a 620 hp BBC with cast oval heads ported by him?. He explains which cores have the best chance of good flow and oddly enough its the later versions with the bigger chambers, he also shows what 99.9 % of the people didnt know back then was casting shift and the good port and bad port scenario. Do you think its possible that the casting process improved over the years from say 68-77 remembering that in mid 70's the 454 wasnt known as a performance engine so i doubt GM cared about flow but might have improved on casting process? I am sure that an AFR AL head isnt affected with such things as core shift, etc. like heads from say 1969. Yes your head swap yielded 80 hp and more torgue and considering they were a bolt on thats very respectable providing someone has the $$$ for the heads, but like anything more power = more $$$$$, great comparison BTW

The small port oval, 110cc heads cost a lot more. GM,DART,AFR etc wonder why?

I wonder how the merlin 269cc flow & make power ? Thanks Richard Holdener