What does it run?

Seems to me that A LOT of the guys that go around telling everyone how great LT4 and AFR are lack the proof in the form of timeslips or at least neglect to put it in their signatures.

 

sounds about right.


Lemme guess...its not set-up for drag racing.

 

A couple months ago I saw a well done stroker setup for road racing outrun all the "strokers done right by forum standards" it outran the rest by .4+ and that was popping out of third gear with the A4 so I think it safe to say there was a little left in it with a full pass.
Besides even if road race suspension hurts the launch it wont impact the MPH that much except maybe to push it UP as I have seen cars MPH higher when they spin as opposed to hook.

The road racing thing is not a great excuse, yes the suspension will hurt launch and ET but it does not completely negate the dragstrip as a proving ground.

 

LOL... well i didn't buy the lt4 heads.. i own a 96 corvette that is an lt4 and have a 280 xfi cam in it now.. but want more.. had a camaro with AFR heads on a 383 with that cam and only 9.7:1 compression and trapped 1 mph less in the corvette and the 383 was set up for drag racing, the vette was stock other than cam, clutch and gears.. i can't launch a car to save my life. and no i wasn't impressed with what the results of either head or time. they both had a good amount of power but i haven't really got the opportunity to drive anyone else's car that was as fast or faster than my own cars. but i want this car to run.. lt4 heads aren't really worth a **** in my book but neither are lt1 heads or any heads really straight out of the box.. and it is not a surprise that you can get a worked lt1 head to flow right up with a worked lt4.. i am not on an AFR band wagon yet i don't really want to spend more than i have to for this stuff.. i have the set of AFR's for a sbc mentioned earlier that i was debating on having converted to work on an ltX and then ported..

 

IMO the XFI stuff is grossly overrated much like AFR and LT4.
For forums to be really useful you have to sift through the dozen kids posting crap to find the one guy who knows something. This is why so many poor parts have such wonderful reputations.

 

This quote gets my vote for the best quote ever on this or any other forum...

--Alan

 

yeah.. i don't really want to reuse it with the new heads whichever way i go.. i am not saying anyone is wrong and taking all advise, especially from AFR owners with fast cars.. lol.. j/k. i am thinking looking at AI's website and there claimed numbers and prices are making them look pretty appealing..

 

I like my lt4s and it was a vast improvement over my lt1s. that being said I also got a killer deal on them or I would have went converted old school or afr RRs for the extra money. My lt4s came in peak of 304cfm with good mid range nembers. You can see the difference the swap made in my sig. If I was building a street car and wasn't woried about et/mph as much as I was about a fun to drive car i would not spend the extra money for aftermarket castings and stick with a well ported stock casting.

 

well ported stockers cost the same as aftermarket heads..

 

and well ported stockers will outperform any of the as cast aftermarket heads. Don't think anyone will argue that.
What they will argue is when I say that for most guys ported stockers will outperform ported aftermarket castings.

The 2 fastest NA b-bodies both solid roller 383s one with Chapman Trickflows in a gutted race car 10.73, the other AI 200cc in a lightened car but still nice enough to put in car shows, leather interior still intact even, runs 10.82 despite being over 250lbs heavier. Kicker is the 10.8 car has only been together since spring and that best pass was in May, just wait till he sees some good fall negative DA weather.
Both still use stock pcms, few years ago the fastest was 11.5 with cnc'd LT4s and F.A.S.T. then 11.2 and AFR LT4s again with F.A.S.T.(9.9 on the bottle). Amazing the advances we have had in the last few years.

 

red94chicken
Since you do have the GM LT4 heads they would have the small combustion chamber that helps make power on the 350.
Aftermarket heads like TFS and AFR would be good for the big chamber and for stroker or forced induction motors. I know that's stating the obvious.
It would be neat to see what Ai can do with your GM LT4 heads.

I have a set of pocket ported GM LT4 heads that I love. I don't have flow numbers and they probably flow poorly but they made good power on my 383LT1, (via trap speed and car weight).

Many have stated that well ported GM LT1 heads are better for 350 ci motors than well ported GM LT4 heads. Any comments from the forum members here as to why? I don't see why the LT4's cant be made to work as well.

Karl Ellwein

 

Seeing as one of the stroker owners I mentioned earlier had a problem with my comparison of the two cars here is the info on both.
You decide which looks more impressive.

http://dan.esteban.com/impalass/Retu...&CompareID=492

 

The TFS combo was run in -2076 feet while the AI combo was run in 1438 feet while being 200+ lbs heaver. I wonder what one makes more power?

 

That link to the combo comparison is excellent.
The Mike Harris Impala SS is the one that Dwayne speaks of that goes from winter time 10.98 @ 122?mph to summer time 10.82@122mph.
The difference being the winter 10.98 is with owner ported GM LT1 heads.
The sumer 10.82 is after Ai ported the heads and also Jesel shaft rockers.
I ran side by side with Mike when he ran his old combo personal best 10.98 @ 122?mph (that's when I ran my PB of 10.73 @ 127mph). So those GM LT1 heads getting ported by Ai really bumped up an already good running combo.
Mike also dynoed 500+ rwhp with his newly ported Ai (GMLT1) heads.

If Mikes combo can be compared to my combo, (an 11.3:1 static compression ratio LT1-383 with 62cc chamber, big valve, fully ported Chapman TFS heads), it shows he makes probably 50 more horses with his 13:1 SCR small chamber, small valve, GM LT1 heads fully ported by Ai)

red94chicken: I still think you can do well with your GM LT4 heads especially if a good porter works on them such as Ai.

Karl Ellwein

 

If you don't like your lt4s I have some stock lt1s I will be glad to trade ya.