What kinda power would a LT4 kit and full bolt-ons make?

 

LT4 kit is a waste of money. You'll make around 375 to the wheels. You can do a lot better for cheaper.

 

yep yep... i wanted to do the LT4 forever until I started looking into other things...

 

 

Well i work at a chevy dealership and get 40% off on anything i pay. so...

 

Well, in that case - to answer your question, I'd heard the LT4 kit with the hotcam would make about 370 at the engine. With full bolt-ons, yeah probably something like 375 at the rear wheels.

Do you get your 40% discount on a GMMG exhaust, too?

 

well, in that case it might be worth it. Still, look into other things. You could always go with the LT4 kit, swap out the small LT4 cam with a bigger hydraulic roller and get the heads ported.

 

Doesnt GM sell a decent cam (aside from the LT4)??? the GM847? or something like that? Just getting your LT1 heads ported and putting in a different cam would give you huge results vs using a LT4 kit. Ported LT1 heads will flow better than the LT4s(though the lt4 heads have a higher potential when ported), just depends on what your after though.

 

375 rwhp is right where I want to be. I'm looking at other ways too. I just wanted to see how much power it makes. Thanks for the help!

Cory

 

get the heads and intake but ditch that Hot Cam on ebay.

 

Agreed...Get the LT4 kit and swap the lt4 cam for the gm 847. Sell the cam on ebay or something. But the LT4 heads with new springs, roller rockers, pushrods the whole deal is nice for our cars and would really freshen it up...that 847 will be a much better cam IMO. Also if you just port match the lt4 heads and intake yourself or have someone do them....that would make some pretty good hp. I'm guessing 400rwhp+ conservatively depending on the porting or not of the heads and the rest of the bolt ons....58mm tb, lt headers...tuning etc....good luck and get me a discount man!

 

I highly doubt a LT4 conversion and full bolt on's would make 375 to the ground. Not gonna happen, just my $.02

 

Well I'm pretty sure on what i want to do. I'm thinking about buying the LT4 kit, selling the hot cam on e-bay or something like that and getting a cc306 or a GM847 to replace it. i'll have the money in about a month so i have time to look into it some more. After i get it all done i'm going to go find dyno and i'll make sure to post the result to let everyone know. Thanks for the help!

 

Yeah, wasn't the 1996 Grand Sport Corvette rated at just 330 hp at the flywheel? I would say the LT4 kit w/ Hotcam does less than 300 rwhp.

 

an LT1 with the hotcam does more than 300rwhp. the LT4 conversion with hotcam will put 330 to the wheels at least and thats nothing. with full bolt ons you can get close to 375, but not with the hotcam unless the heads are worked.

the heads are awsome but they cost a lot and need work to be even better. if you can get them for 40% off do it. theyll support anything you will want to do with the engine.

 

Considering full bolt-ons, I believe 375 rwhp to be an optimistic approach. But I could be wrong. Fastbird has a lot of knowledge and has been in the LT1 game longer than I, so I don't mind being corrected by him.

The advertisement from GM is 425 bhp with only the LT4 kit on an otherwise stock car. With 15% drivetrain loss and full bolt-ons I concluded it to be in the area of 375 rwhp. I have no experience with the kit however, and have heard that it's a waste of money.

This being said, does anybody have any dyno results from the LT4 conversion?

 

lt4 conversion with full exhaust and a ZZ9 camshaft will net aprox 380 at the wheels in a manual car. the ZZ9 is similar to the hotcam, but better in different ways i guess you could say. the kicker though is thats with fully ported LT4 heads. i think 375 is pushing it but possible without boltons. but not with the hotcam.

 

Why does everyone say it is a waste of money and to do this or that? True you may be able to get more power with other combos but look at what you are getting with the kit: Brand new LT4 heads with springs and lightweight valves. Brand new LT4 intake, LT4 hot cam and 1.6 rockers. You also get every gasket you need for the instal. The only thing else you would need is a timing chain. It basically comes down to what you want out of your car. I believe if i put it on my car and in good air i'd be running 11.5's@ 117. I am seriously thinking about doing it. I then could sell all of my stock stuff(no core charges) or even keep them. If i want to go faster later i could get the heads ported and put in a 847 cam. But it really comes down to what an individual wants to accomplish and how radical they want their car to be. There is a guy on camaroz28. com with all bolt ons and just a hot cam running 12.1's@115 putting 355rwhp down. Pretty impressive. A really well tuned LT4 conversion with full boltons should put down 375-385rwhp with a M6. Also take note a 847 cam will idle much more choppy then a hot cam or another "custom" cam with similar specs.

 

The kit costs like 2500 or so.... i paid 950 for assembled heads (well outflow LT4 heads, 278 cfm), 250 for my cc306 cam, 70 for trick flow pushrods, 200 for pro mag rockers, 175 for comp-r lifters, 100 for full gaskets.... that comes out to 1745.

My car puts down MUCH more than 375 rwhp. I put down 355 rwhp with stock heads. Im estimating im somewhere in the ballpark of 425 rwhp. So take that for whats its worth.