Your stroker is thee perfect example of what happens when you use OEM LA cylinder heads. Your cylinder heads probably don't flow anywhere near 275 cfm. It's not really about flow anyways--more about CSA (Cross Sectional Area). Your engine is performing exactly as it should. I built the same thing years ago and I went 11.8 @ 114 mph with a car I drove almost daily. Nobody could touch my car on the street AKA (light 2 light). You will love it--Until you get use to it. J.Rob
At the time I ordered the heads I got caught up in flow numbers not realizing how important cross sectional area/port volume is in relation to cubic inches. I just didn't know. Now that I do I want to correct it. I've looked at the Trick Flow 190's but the port volume is only 190. I'd prefer 210-225. Indy's are out of the question at their $4400 "get in the door" price.
The Trickflows should put you at 500hp or so if thats what you're chasing. J.Rob
Indy 360-1 heads would be overkill for your combo, more likely would hurt performance.
Yes, you'll need more cam if you replace the heads. I'd do the compression math with the new head chamber size before I ordered flat top pistons. You may be okay with what you have.
I've done that. The problem is using flat tops with the Trick Flow's 60cc chamber. Compression is pretty high. I already have a hypereutectic dish piston already. It has a step on it so they have to be replaced to use closed chamber heads. Looks like I may "have" to go with a dish to get the compression reasonable with pump gas.
Any ideas on how much more cam I may need? Specs?
For what you're doing with a 3.55 gear I'd keep it in the 250-255° @ .050 and .575ish lift.
Can step be milled off? I'm not familiar with that piston.
100% right
Can you replace the pistons without having to rebalance?
So, what else do I need to run 10.2: 1 compression with iron heads? Timing, cam. It's got EFI on it now.
If those are open chamber heads, 10.2:1 should be fine...run an NGK 5 plug to start, cam should be enough to make very close to 500HP. Just trying to keep it simple for you. If you spend 1200 on porting and milling, and the EFI is up to the challenge, you should pick up roughly 40HP...you'll have to mill the intake manifold to match (or have the heads intake face milled) and might have to change your pushrods...maybe.
Thanks for that info. I thought I could have some work done on the heads at half the cost of buying new ones. Particularly what kind of porting do the heads need? I assume the ports are too small.
Here's a trick flow 408 515hp @ 5900 rpm 526tq @ 4000 rpm
I'd run what you got and if not satisfied in a few years worry about then, if the 5300 rpm ceiling comes up to fast for you could always put less rear gear in.
I'm guessing quite a bit, especially on the intake side. If you have a tulip intake valve, that's a big problem too. I'd have to see the heads to evaluate them...or you could sell them and the rockers and go TF setup...mill the TF heads maybe .020...you should see a big difference in that.
