GM Performance Parts has an lt4 conversion kit, you get the heads, intake, cam and all the other little goodies to put it together. But at $2500, does it make sense to go this route??
They claim 425+ hp
They claim 425+ hp
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I've seen the kit for less than that.... try Summit, or somebody said "gmpartsdirect" was down to around $2,080 + shipping.
The 425HP claim came from an engine dyno test done by MORE Performance many years ago, and recycled in the past year one of the Pontiac magazines. They got 429 flywheel HP, but used a few parts that were not included in the kit, including things like larger injectors, larger throttle body, long tube headers, and also conveniently forgot to mention that they were using a $3,000 aftermarket computer to tune it. Not saying you can't get 425HP, only that is will cost you a bit more than the cost of the kit.
Some people will argue that for less money you could have your stock LT1 heads ported to outflow the unported LT4 heads, and pick up a cam a little more aggressive than the LT4 HOTcam.
I like the red LT4 intake manifold though....
Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor -
GarretTa what are your goals for the car? A summarized version of what your car is and it's mods would be very helpful in your signature.
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Also remember, you can sell you stock LT1 parts for approximately $500. This brings the total to about $1700 and gets about 75 hp gain...w/tuning. Compare this to the LT1 port route...I've not been able to find ported LT1 heads for much less than $1500. IMO...the LT4 conversion is a great bang for the buck!Al 96 Ram Air T/A
Mods: Build # 784 * Hotchkis STB * SFCs * Borla cat back w/QTP cut-out * AS&M/RK Sports Mid-length headers w/single CAT * Koni SA shocks on lower perch w/ lowered rear * Strano Hollow front & rear antisway bars * 1LE front/rear springs * 1LE aluminum driveshaft * Strange 4.10 gears w/ Zexel Torsen diff. * ARP bearing cap studs & aluminum diff cover* J&M Hotpart poly/poly rear LCAs and poly/poly panhard bar * RAM Powergrip clutch w/ LT4 PP and RAM billet Al flywheel * C5 Z06 brakes * C6 Z06 wheels * Spohn T/A * Spohn DS Loop * fully custom interior w/ custom audioComment
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Fred speaks the truth. More Performance also used the lighter LT4 crankshaft, LT4 10.8:1 pistons, lighter LT4 cam sprocket, etc.) which all of these do not come with the LT4 kits that I have seen. With just what's in the kit here in Summit, I wouldn't expect more than a 65-75 hp gain.The 425HP claim came from an engine dyno test done by MORE Performance many years ago, and recycled in the past year one of the Pontiac magazines. They got 429 flywheel HP, but used a few parts that were not included in the kit, including things like larger injectors, larger throttle body, long tube headers, and also conveniently forgot to mention that they were using a $3,000 aftermarket computer to tune it. Not saying you can't get 425HP, only that is will cost you a bit more than the cost of the kit.
http://store.summitracing.com/partde...%2DGMP3287%2D2
Since we don't know yet what your motor is let's just say you are making about 325-330 hp stock. That kit would only give you 405 max I feel. And that may be even a little optimistic.
I think in the long run you could make much more power by going with a heads, cam, and intake kit such as the one below for basically the same price (scroll down to the bottom of the page to "Power Pack II"). There are many other packages out there like as this one, I just used this one as an example:
http://www.lt1f-body.racenet.net/valvetrain.phpComment
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