I need some help. I am thinking about doing a lt4 conversion. I saw the kit in summit for like 2400.00. First is that a good price?Second I never relly did that kind of work to an engine before is it really something a engine builder should tackle?Third I have the a4 tranny would I have to beef it up?

 

First off, do a search for exactly whats in your subject line. This question is asked at least every other week, there is some good info about it in some of the threads. From what I here though, its not worth the money, you can gain more sending your heads to Llyod have them p&p'd, larger valves, all the good stuff and also get a much bigger cam in there then the hotcam for that kinda money. Thats my opinion anyway..

 

it depends on what you want, If you want to say, "I have a LT4" then go for it, I haven't been able to get on it yet due to clutch break-in period, but more than likely it's not worth the money. I will probably end up port and polishing my LT4 heads and getting a bigger cam later on.

 

Heads, intake, cam, and rockers do not an LT4 make..
There's a lot more to it than that, if you want to convert to a 'real' LT4..
I'd go with P&P heads, and a cam [cheaper, and will make more power]

 

See, I really want to see some dyno charts on this. GM boasts that their conversion kit will net 425hp at the flywheel after tuning. WHy would GM make that bold of a claim?

Also, I called Don Lee Auto in Rancho Cucamonga about porting my heads and he actually recomended I buy the LT4 conversion rather than having him port the heads because he claimed the LT4 conversion would make better power and be a better platform to port and polish.

 

Well the LT4 heads have better "potential" for porting but unless you are going with a HUGE cam and a HUGE port then just port your LT1's and save some cash.....just my .02



Chris

 

GM makes that claim because it's close to true, except that the tests were done under conditions and w/ bolt-ons that included more than just the basic conversion set-up. And the hp figures refer to FWHP, not RWHP. Plan on spending considerably more than $2400 when its all said and done, especially if you're going to machine the LT4 heads/intake.

Not sure who Don Lee is, but others have posted on this thread about porting your LT1 heads and getting a cam (the LT4 Hot Cam is fine). The ported LT1 heads will flow better than stock LT4's, the set-up will be cheaper, and you will realize more hp/torque.

I suggest you do a search on the topic (as has been suggested above) and after really doing your homework, go w/ what you believe is best for your performance goals and budget. Just be aware that whatever path you choose, the cost will be greater than your initial estimates; always is. Hope this helps!

 

I really wonder why GMPP, Summit and other places that sell this conversion kit don't at least mention that headers are required to see these numbers. Noone is going to see 425 at the flywheel using the stock LT1 exhaust manifolds , even with tuning, let alone with the lousy stock air box. Most people here know that but the average guy out there probably takes those numbers as guaranteed when he buys it.