What are you guys coming up with for port volumes on these heads ported, 240ish cc? I am working with the early castings that start out very tiny and right now I am at 240 cc.
My stg3 ended up in the 280cc range but my pushrods are offset .400 from stock.The valve bowls are huge compared to the way they came.We also laid back the port wall opposite the head bolt from the valve bowl to the port entrance.
Jeff, If my memory is correct (remember.. I am 40 now) Gary Ks heads had runners that were 240 cc and flowed 325 max cfm.... my Stage 2s had a 248 cc runner and flowed 336... my Stg 4 has around 265 cc runner and flow 353 max. I hope this helps ya! The angles on the seats and on the back of the valve are more important that runner volume. Later
I agree with John with the seat angles.There is a lot to gain in the valve job we have tried a multiple different angles to gain what we have.The actual angles will depend on the valve bowl shape and chamber shape.But all in all the VJ is where most of your improvements will come. When we did my heads we went big since it was a 523 cid nitrous motor.The port needed to big to help pass the volume of Nitrous we planned on useing.
Did a little more flow test Christmas eve and was very happy with the results. Not really sure why the intake dropped off at .700 lift but it doesn't matter in my case the cam won't be that big, "under .650 lift" . Looks like the low lift were real good. Thanks for all your help guys. Merry Christmas! ----Intake---Ex .200- 166 135 .300- 228 186 .400- 278 227 .500- 327 246 .600- 350 259 .700- 341 265
Hey Jeff, Merry Christmas!!!! Those are some nice numbers..... they are with a percent or two of my stage 4s. Your results for max air flow @ .650 to .700 lift is very similar to what I have seen on a flow bench. I think as the valve moves out of the cylinder head it gets too close to the cylinder wall and creates a disturbance in the air flow which causes the flow to go down. This has happened on every set of Buick cylinder heads that I have had on the flow bench. It happens anywhere from .650 to .700 lift. If you had an extra valve it would be interesting to see what would happen with a 2.200 intake valve. I have seen flow numbers posted where the flow continues to rise all the way up into the .750 to .800 range. To do this different valve angles or seat angle or something must be done. I have not found the secret yet. GREAT JOB!!!!!
I owe alot to you, my cylinder head guy "Bob Bruneau" and a few other guys on this board. Bob is amazing, his sbc heads flow 350 cfm. He builds Busch North engines and wins alot of races. Are your stage 4 flow #s posted here anywhere?
John, Care to share what back angles on the intake valves you have tried? Going back to the flow bench on Saturday and thinking of trying a few different valves.
angles Were just finishing a set of stage2 TE's, they flowed great. We tried 6 differant back cut angles with no gains, the old stand by worked the best :grin: And I would like to add this is the second set of TA heads not to crash after .540 lift,I'm a happy man :grin: Chris
Chris, So what the flow #'s? What I mean is the angle on the back of the valves as in shape like tulip exhaust valves. Not the back cut angles.
should I port the stg 2 TE's ? If you were building a 10-1 motor with STG 2 TE heads... would you spend the money on port work? I would like the most out of the 455, but I would rather not spend $750 on the porting if it only makes 20 more horse. I'd buy lighter doors for the car instead...
Valve Sorry, it sounded like you were looking for back cut angles. We've tried some high priced dodge and BBC valves the only one that out flowed the valves I get from TA was a BBC titanium valve and don't qoute me but I think it was 18*s but it was only by about 9 CFM over all the lifts so I didn't think it was worth spending a wack of money for that little bit of air flow gain . Chris
Flow sheet Adam, do you have a flow sheet to go with that mold. I can see a BIG differance on the short turn compared to what we do.Chris
I was not sure if you guys were going to understand what I meant. I should have been more clear, but still good information on the back cut angles. :TU: Thanks I am also back to playing with iron heads. Trying some big titanium intakes and more bowl work. I spent so much time on my irons I cant part with them.
