Thanks a lot Mark. I'll be able to finish my heads now. I'll be trying to replicate this tomorrow. That will leave me with one completed head and one to go. Creating the venturi on the one side of the bowl and getting the short turns is the trickiest part. I'm going to print up some screen shots for the final pull on this head. I took these off the shelf just because of this series. Very inspirational. Love it.
Mark + Tommy, I have been home a few days with the flu, and been catching up on your video's. I am very impressed by your articulation and thoroughness of the content you are providing. I think that by the build and test on the strip segments, you have earned my business as a first time customer. It's refreshing to witness real world testing unlike some of the other SoCal Dyno cells. I will be reaching out soon to source a new BBC. Keep up the good work, it definitely does not go unnoticed! Dan from NorCal
Great job on Videos always awesome. I would still like a real comparison with same valve diameter to have a real life gain on porting without changing the valve side or even and or, change valve with no porting and flow to see the gain. These are just suggestions I would like to start porting heads I watch videos but I think I would start with someone with experience by my side! Thanks again and keep doing your great job!
Awesome video series guys! This info is tremendous! Thank you for taking time from your busy schedule to share this stuff. Want to try this on my closed chambered exhausts. My engine really noses over past 6500 too.
Hey Mark, Do you care to show us the exhaust valve you use in this head...? When it comes to the exhaust, the shape of (the back side of) the valve is as much a part of the port as the port itself...
You’re porting the heads to try to gain airflow when your problem is very likely that the hyd lifters are collapsing at the higher RPM. 6300+ is always a stumbling block with the hyd lifters these days. Installing solid lifters on that same hyd roller profile probably would have probably pulled much higher before falling off. I’ve made 625hp /625Tq on 496’s with 2.125”/1.75” valves and no porting on those heads, with a mild cam and pump gas.
Mark what are the flow number for the intake side? Any where close to 330cfm at 500? I’m building a 467 with 781 heads and a tunnel ram with 660 holleys.
I have a 94 ,454 engine. Is the iron heads worth working for a street performance build. Mild porting, and converting the rockers? I'd like to swap in a mild cam, i already got a performer rpm airgap intake and long tube headers , should be 330, 340 hp. And 440 tq. I have seen a equal engine a dyno. I want to keep the lower compression , maybe add a turbo. I hope to have 600 hp & tq on tap. for possible daily decent mpg (for a BBC!) 15 mpg in town , maybe hyper mile about 25mpg on the long roads! I have overdrive. About 3.08, and about 5,000 lbs... Should I just look in to a set of older oval ports. Or can these be worked? And with about 10psi... Great video. I don't know that much about the newer BBC stuff. I'm at home with SBC stuff.. Thanks
Mark, I saw that you scribed out a mark on the head of the chamber. Is that scribe mark the actual head gasket size or the cylinder size? Great video and I hope you get paid dearly for sharing all this information with us.
Mark I see some guys claiming a cam with a higher duration and valve lift on the exhaust side (more lift and due at 50 than the intake) that you are leaving power on the table. If that’s so then why do so many cam companies run a dual pattern design . This is for stock heads, 781 to be exact. I. Running s lunati solid 247/255 612/ 635 lift would I be giving up power in my iron head 10.5 to 1 467 ...?
There is so many factors, big cam grinders are trying to cover as many people as possible, to get the most out of your setup always go with a custom grind, and yeah afr 265 heads with the cnc porting are the best aftermarket head in that cc range available, but you might talk to Tony mammo of mammo motorsports first, he helped make all those afr heads work so well
Everybody works on Ls1 engines these days Haha there is heaps of info out there mate just have to look for similar application as what you are aiming for. Most engine builders dont go outside of what is common because it's not necessary. I actually didnt have some factory parts and had no choice in going a different direction. I'm far from a engine builder but there is plenty enough info out there for the ls1. Practiaclly everything done in a backyard shed or under my house except head machining. Aiming for a reliable and cool running 430hp at the wheels with the ability to get 470+ on a leaner air fuel mix. In case I end up in a traffic jam I'd rather more fuel being dropped on the piston so it definitely wont over heat which seems to be relatively common with most of the mods I have done. Bottom end is standard except the cam and oil pump. If you are keen to know what I have done or if you have any questions I can help with let me know, I really dont mind. As I said I'm no engine builder but know a few and they are very excited about the fact I didnt listen to their advice of doing the same as everyone else. Ls1 is a easy and cheap motor to get reliable power from especially doing it yourself. Porting the heads is probably the hardest part to do yourself but that's one thing done on mine that engine builders and even a professional head port shop owner was extremely impressed with on mine. Research and confidence to have a go yourself is key mate. Bit of thinking outside the box never hurt anyone that bad it's just wise to get advice on what you are keen to try. If they tell you its unnecessary or pointless ask why and if it's going to be better than not doing it at all. At the end of the day it's the tuning that makes it work and he will need to know as much info as you can give him.
dragginwagon406 so in theory unless it’s a dedicated strip car it’s not really worth doing any more than a clean up port if you were to retain stock valves?
@@Spudderr, depends on how you look at it...for several hours of research and a few hours with a die grinder, you can pick up 40 hp. In my book, that's mandatory. Add 2.19/1.88 valves, and porting done right, the difference can be 100+ hp obviously much more power available, if the rest of the combination is on point.
all said and done how much would a pair your ovalport heads cost after you selected the ones with the least amount of core shift redid the valve guides and ported the cylinder heads opened up the valves for the new valves seats you did all that good stuff valve springs new valves how much is all that cost let's have a number for a pair of heads overport ones from you please
the reason I'm asking how much you spent on your cylinder heads because I built a motor myself before 68th that's all it was then I used aftermarket cast iron cylinder heads on it because at the time I could not find any factory square Port hits I had a total of $1,500 in my world product grumpy Jenkins cast iron square Port heads how much did your heads cost did I spend too much because we know how much your heads give you your horsepower I want to know how much you spend on them heads to get that horsepower and I never sent you hate mail I think you misunderstood it send it back to me in this text so I can please respond because talk to text on my phone does not always put down what I say oh yeah my 468 cubic inch big black Chevy made 735 horse and yes I had way more than 9.9 to one compressor
