LT4 Kit for LT1

[MOMO96Z]

I the new Summit book they have a Lt4 kit for Lt1 camaros. They include the heads, hot cam, intake, roller rockers and head gaskets for $2,300.00 . Is this a good offer they caim it makes up to 425 hp with the right computer changes. Or are their any more changes need to be made besides headers.

[wolfdogs]

polish up the head and intake ports.

you will need a 52mm tb also.

and get the LT4 extreme duty timming chain kit... a must.

send the pcm to Ed Wright at Fast Chips for programing with a spec sheet.

you will crank out in the low 400's for sure.

[Bandit]

LT4 intake and heads are a waste of money, also larger TB. as Ken said port and polish the heads and intake, add the chain and computer programing and you are good.

stock LT1 heads are very good, and bigger TB is a waste of money.

[N20LT4Bird]

Ive got the conversion on my 96 WS6, with some additional port work on the heads. I also have headers, exhaust, and a 58mm T.B. among some other minor bolt ons. I dont have dyno numbers, but without the N2O, im running through the traps at almost 109 mph.

[markd79ta]

I have been eying that kit as well. It sure would be nice. My guy here rights the programs for high altitude, and does one awesome job, and his shop is about 1 mile from my house. I would also do the 52mm TB. It would sure be cool! However, I need to build the bottom end first and buy a new k-member

[M3EATER - GG '00 WS6 T/A]

Originally posted by N20LT4Bird
Ive got the conversion on my 96 WS6, with some additional port work on the heads. I also have headers, exhaust, and a 58mm T.B. among some other minor bolt ons. I dont have dyno numbers, but without the N2O, im running through the traps at almost 109 mph.

Well, let's see.....

I did 106 mph stock with just the Lid & K&N (LS1). That combo with an HPP-3 dynoed at 323 RWHP.

109 mph..... means a pretty good RWHP.

Gordon

[Injuneer]

The Summit HP claims appear to be based on an engine dyno test done by More Performance about 3 or 4 years ago, and recently republished in Pontiac Enthusiast. More was criticized at the time for failing to fully enumerate the changes they made to the engine, to get their result of 429flywheelHP.

The engine used Hooker LT's, a larger throttle body, and the engine was run with/tuned with a $4,000 MoTeC engine management computer. So... the $2,300 kit acutally involved about $7,200 worth of material, and untold labor. I suspect there were other modifications they conveniently forgot to mention.

You can't expect 425HP with just the kit and a mail order tune. And to use the torque curve of the HOT cam, you are going to need steeper rear gears, and a looser convertor on an automatic.

I think this is why people downplay the "LT4 Conversion Kit". I think it is incorrect to state "the LT4 intake and heads are a waste of money"... more correctly, you could get similar results with a lower cost approach, involving well ported LT1 heads and a good cam. But I have seen a lot of people screw up this approach. It is hard to find guaranteed high flow heads, with consistant results. So, the LT4 head/intake/cam makes some sense for some people.

The LT4 heads have more potential, as well. Port them and work the intake correctly, and you can approach 300cfm. I like mine .

Nothing wrong with the LT4 Conversion Kit, as long as you know the claims are a little inflated, and that there are ways to do the same thing with less money IF you know what you are doing.

[Eric 97LT4SS]

I had the following installed on my LT4: Base - RWHP 301 TQ 305

LT4 HOT Cam, no EGR
Original LT4 Heads/Intake Ported & Polished
Extreme Duty Chain
BBK 52mm Throttle Body w/bypass
JBA 1 5/8 Headers with Random Tech Cats
Comp Cams double Springs & Pushrods
JE Pistons which kept the 10:8 Compression
MSD 6-Plus, NGK Plugs, G2 SuperWires
SVO #24 Injectors
LT1 Edit Custom re-program
Original SLP Dual-Dual Cat-back
1LE Intake Tube, SLP thermo, & Granatelli Cold Air MAF

With the Redline set at 6,700 RPM's I got the following #'s:

RWHP 361 TQ 349 (Don't have the Dyno runs with me)

Just thought I'd pass on the info for those interested!

Eric 97LT4SS

[N20LT4Bird]

M3 eater - thats an LS1 right? I've got one of those G-tech meters and it says that I am putting about 350-360 horse to the rear wheels. I dont know how much to believe that thing, but by looking at your numbers, its probably not far off.

[N20LT4Bird]

I would imagine that the advertised 425 horse is at the crank. So, if you added 20 percent to 350.......calculating......highlevel math......420. Right? So I dont think the advertised is too far off.

[M3EATER - GG '00 WS6 T/A]

Originally posted by N20LT4Bird
M3 eater - thats an LS1 right? I've got one of those G-tech meters and it says that I am putting about 350-360 horse to the rear wheels. I dont know how much to believe that thing, but by looking at your numbers, its probably not far off.

Yes.... LS1

The G-Techs are pretty good, If you have accurate weight info & have it leveled and aligned accurately. What they are best for is comparing gains for modifications on the same vehicle.

I don't remember the actual numbers, but when I ran a G-tech, I think it showed somewhere in the 325-ish area for RWHP.

All of this is before headers.

Gordon

[Rob]

I ran 111mph with stock LT1 heads.

Pops ran a best of 113.x with his LT4 HOT, intake, heads car. But it weighed 200 lbs more than mine.

I dynoed at around 325rwhp and torque. Same day, he dynoed 370rwhp and 360rwtq. Its been a few years so I don't remember the exact numbers.

Both cars were basically identical except I had SLP dual cat headers into the stock y-pipe. He had SLP single cat headers into a SLP y-pipe and no cat. My car was a 96 WS6 Formula, his was a 95 Comp TA.

Best I ran was 12.4@111. Best he ran was 12.2@113.

No exotic programming or tricks. All the bolt ons and LT1 Edit. It can be done.

[Rob]

Eric 97LT4SS
Those small headers are holding back the power. Very small. If you keep the cats, I'd recommend the SLP dual cat headers.

When I went from stock manifolds to the headers, I picked up .3 sec and 2 mph. 12.7@109 to 12.4@111.

[coloradoformula]

I too was considering the LT4 conversion kit. Only question I have is if I will still be able to pass Colorado emissions. Until I know for sure I think I'll wait.

[Rob]

Mine passed IM240 treadmill back in 1999.

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