Here you go. And only $89.99.
http://images.google.com/imgres?imgu...%3Den%26sa%3DG

What about having an engine builder blueprint the motor. Possibly bore it out a bit and use higher compression pistons?

 

yes he did. he kept with stock cubes and the low end was terrible.

 

[QUOTE=96LT4;1572434034]Nothing has been done to the heads or intake other than swapping out the springs and adding valve guides.
QUOTE]
You might considering some of the following...I did them all and more..

1). Did you port match the intake and heads to the .....777 gasket

2). Upgrade to a 58mm throttle body (with integral airfoil of course)...and modify intake to match

3). Throttle body by-pass

4). Remove screen from MAF

5). Reinstall Head using a .029 or thinner head gasket to up the compression

6). Get your heads & intake ported by a skilled craftsman....a head is a head but very few have ported an LT4 head

7). Get a three angle valve job as part of the porting process

8). Not sure what valve springs you used, but the wrong valve springs can suck up a few horsepower... FWIW I used the CompCam beehives

9). If you are really worried about low end torque put in 4.10 gears

10) New dyno tune to tweek for the increased air flow

Or go get it supercharged.....friend did this last winter and has a great running Grand Sport with over 400 RWHP with great street manners

Good luck in your quest for a few more ponies

 

i don't think that is what he did wrong. you could take a grinder to any head and make it way worse then you started out. llyod elliott and advanced induction port these heads all the time without issue. i would love you to back these statements up with facts like before and after dynos, time slips, flow numbers..

 

Here is my experience with ported LT4 heads.Stock LT4 bottom end and 224/230 cam.Switch to ported lt4 heads(LE)and lose power and tq everywhere.Redo valve job and replace valves, regain what I lost but make no more than stock.Return heads to Lloyd Elliot for refund(minus what I spent on them and he gets a better product to resell).
Disclaimer:
I am not knocking Lloyd.He was very helpfull and communicated with me and the installer/tuner freely to try and help resolve the situation.His work has improved many people's numbers,just not mine.
Turns out my motor was eating itself up and soon expired.
What I learned about LT4 heads is the runner volume and cross section is large for a 350 c.i. motor.When porting both of these are increased resulting in a loss of velocity which doesent help low end or midrange numbers.On a larger motor or one turning high rpm's where low speed response is'nt important it will work sufficiently.
My advice to the original poster is to switch to AFR 195cc CNC heads that flow more air and maintain port velocity.This is what I have done on my 383 and the results are impressive(to me).
Porting of the intake may help(or hurt if not done properly)and a 52mm TB should help with enough airflow improvement on the head side.
I am by no means an expert,engine builder,or know it all.This is my experience from trial and error.

 

AFR 195 comp ports. I believe there was a member here who pulled 420rwhp with those heads and a hot cam.

 

post #25 was pretty close to what he said "if memory is correct".

i believe the heads were ported out to roughly 220cc. a tad big for a 350 in most ppl's opinions on here i am sure.

sorry, no dyno's or timeslips. he didnt race the car like u do.

 

I really think this thread is perpetuating some incorrect information regarding LT4 heads...

The first step in porting heads is to improve airflow....not just hog out the runners

On the LT4 heads a good size for port matching is the ----777 gasket.

This is a good article..
http://www.chevyhiperformance.com/te...ing/index.html

BTW I am NOT hung up on the LT4 heads and recognize there are better heads available, I just don't buy into the big loss of low end torque..and who races at 3500 rpm anyhow???

The two examples given...one is based on the buttmeter the other on a dying engine



BTW here is another project using LT4 heads

http://www.customclassictrucks.com/t.../dyno_run.html

 

my car isn't for racing.

 

ok.

 

aside from swapping the motor, diff and a few bolt ons its exactly the same as the day i bought it. don't know how that qualifies that as a race car. its been to the track ten times since i bought it in 2004.

 

should i use your line?

 

From what I've read the LT4 heads flow a max of 240 cfm. A good set of aftermarket heads, like AFR Eliminators, will flow that at .400" valve lift and as the valve lifts more, the flow increases. IIRC, something on the order of 25 cfm on just the standard, non Competition Ported versions.

Oh, and yes, 220 ccs is much too large for a 350; air velocity and low end torque would go down the tubes with ports that big.

Even one engine build-up featured in one of the mags said that 195 cc ports are too big for a 350 CID engine. I can't recall now if they opted for heads with smaller ports though, but I do recall it was a definite concern. Bigger ain't always better, contrary to what some believe.

In their wisdom, GM went with 195 cc heads on the LT4; I've never seen their reasoning on that move though. Perhaps sticking with a short duration cam with 115 LSA factored in.

Making the heads flow more without dramatically increasing the port volume, to me, is the way to go. I definitely factored that in when I was deciding between 200cc ports and 180cc ports for my son's 96 LT1. When I measured them, they were 189 and change. So although advertised as 180s, I wouldn't have known the straight skinny had I not measured them.

Jake

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