Cut through the BS..are max effort LT4 heads worth it over lt1s?

95Bird · 07-17-2002, 10:53 AM

I've heard that when the porting starts that a lt4 setup isn't worth it from some people and some others say that they are. What do you guys think with my setup. I have a 12:1 355 with 2.0 1.56 lt1 heads. Cam motion Solid roller 255/263 @ 50 656/628 lift on a 110 LS. Would a max effort LT4 head and intake be worth it in my situation. Ive been told that .2 to .3 could be picked up just by switching(of course bigger valves etc.) What do you guys think. Could 20-30 hp be picked up by switching over to lt4s. Maybe a AFR lt4 setup? Anxously awating your opinions.

Thanks,
Tim

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95 firebird Blueprinted and ballanced 355, ported lt1 heads, custom cam motion solid roller,Moser 9" with 4.57's and a locker just to name a few.
11.23@122.25 1.579 60'

2001 NFRA LT1 NA Winner

More on www.geocities.com/herrint

drop top steve · 07-17-2002, 12:01 PM

Depends on how good your lt1 heads flow now. Bigger valves "should" help flow #'s, the raised runner helps. I think I would look at the AFR heads. Be a spendy 15-20 hp, but your at that point, no cheap hp to be had.

95Bird · 07-17-2002, 12:09 PM

well I would like to do the AFR 215 RRs but with the cost associated with converting its kind aut of the question at this point.

I don't have any flow numbers on my heads. They seem to be doing pretty good. I hope to squeeze into the 10.9 range when the good air returns. My 11.2 at 122 was spinning and with some "problems" that i have found and corrected since then.

but your are right on one thing. Seems for me to go faster I'm gonna have to spend some money.

Anyone else?

Tim

[This message has been edited by 95Bird (edited July 17, 2002).]

squinn · 07-17-2002, 05:01 PM

Tim I really think you would see more going to a FAST ECM, then you can really start to make power

We had seen .25 and 3 mph on my car when we switch over. Over the winter we had switch my bother Mustang from stock to FAST and the car went from 10.78 @ 124 to 10.42 @ 127, and when the air gets good again I feel we'll be in the 10.teens.

For the money I feel FAST is the way to go, if you do end up going this way I would be more then willing to help you out. The wide band o2 is a must.

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Steve Quinn
95' Z 350 NA auto
1.44 60'
10.543 @ 127.04

Stock block, pistons, rods and crank.

New NA motor coming soon....

www.norushracing.com

OneFlyn95z28 · 07-17-2002, 10:04 PM

So use stock un touched LT1 heads and a fast system and run 10s? I AM IN!!

I will bet you are going to want me to gut the car though

Sorry not going to happen

If you compare LT1 heads and LT4 heads both ported to there limits LT4 heads are going to cone out on top all things being equal. Sounds like you need to go to a better head then that though. Me? I plan on running low 10s high 9s on my crappy LT4 heads and over 3,600 race weight

Good luck!

BTW I was kidding on the FAST, just the way you guys changed subjects on a dime

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Ellis
Team Captain
Team North West F-Body
www.teamnwfbody.org

KTamez · 07-17-2002, 10:33 PM

I think the important thing is that if you have what you are feeling is a nice set of LT1 castings, then its probably not worth your time. A decent outlay of $$ for a marginal gain.....

A Large cc AFR though might be up for the call though? However to take advantage of a larger head/larger cam (more RPM), you'll be needing the FAST Steve mentioned.

Kurtis "FAST Equipped" Tamez

squinn · 07-17-2002, 10:50 PM

Where do you get stock un touched LT1 heads?

Heads are far from stock, car is far from gutted, but yet everyone has there own feeling on what gutted is.

The reason I would look to a FAST ECM is the stock pcm limits you too only 7000 rpm before it cuts out. With Tim's sold roller I would think its just starting to make power at 7k. As my little hyd roller 240/251 108cl, made peak at 7000 and was still making good power at 7500. Power was 581@7000 550@7500, this was a 350 lt1, crankshaft power.

OneFlyn95z28 · 07-17-2002, 10:56 PM

And like I tried to mention. Where did that come into the head question

My car has FULL interior and ALL the creature stuff

Good luck all!

Ellis

95Bird · 07-17-2002, 11:27 PM

Great idea Steve. I guess I just need to save my duckies and go for the fast system. Was that .25 and mph change with no other changes in the same weather? What exactly do you gain over lt1 edit etec. I'm very interested in this setup. I'm pretty sure that my heads are choking this cam down so I could pick up some with a 215 setup..but like someone else stated I would need the fast system to utilize the new powerband etc. I know it pulles all the way to when it start to cut our or hit my rev limiter...I can't really tell which it is. Limiter is set at 7200 now. Hey, do you get away totally from the opti setup? Do you use a crank triger at that point. Is there somewhere I could read about this system.

I was also thinking of the 210 AFRs if I did make the change without going to the 215 setup. I think both would give me the ability to make power in the mid to upper 7000 range. But then we are back to the pcm stuff. Man, this could start to get expensive...:P

Thanks again for the help guys.

Tim

[This message has been edited by 95Bird (edited July 17, 2002).]

KTamez · 07-18-2002, 12:00 AM

Quote:

<font face="Verdana, Arial" size="2">Originally posted by OneFlyn95z28:

My car has FULL interior and ALL the creature stuff
</font>

It should be noted that these cars are running in the 10 second range w/ no spray.

Little bit different scenario.....

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Kurtis Tamez
LT4-396.com
97 Z28 LT4-396
94 Firehawk LT1-396
Team NW F-Body

OneFlyn95z28 · 07-18-2002, 01:05 AM

I well under stand that big boy

I am not running tens yet either. and when I do? I will still have all this stuff in my car

Street cars are no fun with out all that stuff

Squinn is fast and I respect that. Then again we went from a heads discussion to a ECM discussion and no answers were really given.

I may never run 9s or 10s BUT if I do you can be damn sure I will be coming down the return road with the A/C on

Like it or not

Now we are even further from the subject then we started.

So you Big dogs have fun and us Puppies will stay in the corner because we are not good enough

Ellis"who cares what the subject was'

kmook · 07-18-2002, 01:13 AM

Quote:

<font face="Verdana, Arial" size="2">Originally posted by OneFlyn95z28:
I may never run 9s or 10s BUT if I do you can be damn sure I will be coming down the return road with the A/C on
</font>

Preach it brotha

N20Dave · 07-18-2002, 09:12 AM

AC is for winmps

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94 Formula M6
Last year 10.98 @ 126
355 stock heads, P600

In the works:
383 worked heads, D1, th400

KTamez · 07-18-2002, 09:27 AM

Sorry Bud just tryin to get you to compare Apples to Apples, instead of Apples to Oranges. If I build a Pratt and Whitney Jet Powered Limo, is it better then your car cuz its got a cocktail bar and goes 6s?

Sorry for the lack of content Tim.

For what its worth you have a great running car, and depending on just how nice your LT1 castings are, its probably not worth swapping heads unless you get into those AFR 210s or better. For your Situation/Setup, I think Steve is definetly a guy I'd hold some regard in what to do though.

I only hope my stroker with 396 more cubes can keep up with his 350. Suppose I could make excuses....

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Kurtis Tamez
LT4-396.com
97 Z28 LT4-396
94 Firehawk LT1-396
Team NW F-Body

squinn · 07-18-2002, 06:44 PM

Well Tim for starters you can spin it past 7k

I've never programmed with LT1 edit, was not out when I went to FAST. On the fly programing, real time wide band o2, you can set it up to run off the o2 to correct at WOT. I find FAST very easy to program, but yet I've been playing with for 4 years now. You can run without a crank trigger, but for high rpm its a must. I run a Holly hal effect crank trigger, some fabbing is required, if you need to see pic I can send you some.

As for my gains it was cool out when I had done my base line, and hotter out when I ran the fast system. After changing gear, stall, tire size, a few odds and end, lots of flogging on the program I had drop 1.05 sec off my ET.

As for your LT1 heads I think there is still more in them, You might look at getting a ASM monoblade to get more are flow. I' hope to let you know what the limits of the stock heads are after I get my solid roller motor together.

Steve