How big of a difference is there, on average, between flow numbers on hogged out sets of heads?

Like say, LE3 versus a comparable port job on LT4 heads?

I heard LT1 heads have more room for port work, but LT4 heads flow alot better in stock form. For a heavily modified car, is it worth it to convert to LT4 heads and intake that are ported versus LT1 set up? Just wondering. I dont have the money yet for this jump into the project yet, but it just has been on my mind lately since my friend just bought a LT4 Vette

 

About 20-25CFM.
If ya got a big engine go with AFR 227's.

 

Big engine as in 383/396?

 

YES & 406-421-434-454

 

I wonder how they would be on an 383 low compression supercharged motor. This is what I want to one day do with my camaro once I get the money. Make a low comp 383 supercharged street car.

 

Would it be worth it, to put those AFR 227's on, if your still running an LT1 intake?? Granted the intake has been ported,material removed/welded above the injectors,etc...Would that intake choke those big heads??

 

Unfortunately the AFR 227 heads are considered "LT-4" style and MUST be used with an LT-4 intake. I believe that the only AFR head that works with the LT-1 intake is their 180cc runner head.

 

I just cheched out their site, that is apparently the only LT1 head they make, so you would have to switch to an LT4 intake too to run any of their other head set ups.

I really wonder how these heads would be for a forced induction 383 street car.

 

I'm getting a 9:1 383 LT1 long block done up now. It's gonna be running 10psi with a 100 to 150 shot on top of that. I stuck with a nice set of ported LT1 heads. I'm sure I wouldn't outflow a done up LT4 head, but they would probably come close. Bang for the buck though and if your not worried about squeezing every ounce of horsepower out of your setup, I think the LT1's are a nice setup. My dyno numbers will somewhat tell the story though and then the track.

Ken R.

 

RogueDriver: That is almost exactly the kind of set up I want to build. Could you PM me and let me know more about the project. Im really interested in the head/cam you have set up for it. And Id love to see the numbers it puts down w and w/o the spray

 

I have a set of LE2 heads that are a LT1 casting but for the LT4 intake with 2.0/1.56 valves that flowed 274.4/185.6 at .550 and 272.4/190.9 at .600.
These heads along with a GTP6 236/242 and .597/.583 lift cam with 114 lsa produced 446rwhp N/A on a 383 motor.
So the LT1 castings can be made to flow exceptionly well, I'd think the difference for a SC/turbo application would be nil since your forcing air into the cylinder anyway as long as the boost in the intake is making it fully into the cylinders, it it ain't, then crank up the boost

 

Flow the intake after working it and see. If the intake flows less than the heads, you'll see a loss proportional to the difference. If you can get it to flow the same or 5% more, then youre sitting real good but that's probably not going to happen with a 227 at full potential.

-Mindgame

 

what happens if the head is too big like a fully ported afr 227 on a stock crank?

 

It won't be too big.

 

Well, Jordan Musser did the intake(LTx version)so, Im sure that thing will flow. Now, the current worked heads that are on it, could be a different story..Care to see the flow #'s for them? Or take this to PM's? Im curious..

Adam