dchildress

I have a 94 LT1 6 speed. Since the wife is getting her new toy (02 Trans Am WS6 6 speed) I would love to add a little kick to my toy just to make sure I don't get outrun. I have K & N w/open lid, Hooker shorties, Corsa cat back, and even one of those lousy air foils that was in there when I got it. Before I even owned my Vette I was wondering about the LT1 to LT4 conversion. I have a guy who I trust to pull the motor and do the conversion along with other items (Opti, water pump, front & rear mains, new flywheel/clutch assy). I am looking at the GM Performance Parts kit at Summit Racing.

I just have a few questions:

1. What kind of power can I really expect? I read 425hp, but how close is that?

2. What kind of driveabilty issues will I have after I get it tuned?

3. For $2330 for parts is it worth the price?

4. What other mods will have to go with it?

Thanks ahead of time, guys.

mothersworry

1. What kind of power can I really expect? I read 425hp, but how close is that?

A true LT4 only had 330 hp. The kit you are getting must have lt4 heads that are ported. What cam are you going with? hot cam?

2. What kind of driveabilty issues will I have after I get it tuned?

It should be very streetable with 425 hp

3. For $2330 for parts is it worth the price?

I would just have my stock heads CNC'd and get a nice cam. Something like a 222/230 112LS. You will probably save a few hundred dollars this way.

4. What other mods will have to go with it?

Dump the shorties and get some long tubes and a 3" cat back. With all these changes you will have a great streetable setup.

dchildress

Thank you for your response. I am not sure if the heads are ported. I am assuming the kit comes with the LT4 HotCam and 1.6 rockers.

I know the long tubes help the top end but I am a firm believer in keeping cats. Does anybody out there have some pics of long tubes with Corsa/BB cat back AND cats on it?

Red Guts

...or sell your car and buy an LT4 (or LS1). Sometimes that's cheaper in the long run.

dchildress

DONT LET MY WIFE KNOW THAT!!!! I am kind of attached to my 94 plus its been paid off for a while. Hoping to add a C5 to the collection later next year. We already have the C3 & C4.


I am tying to get some more information. I am a big fan of pre-engineered kits so everything matches everything else. I am already assuming I will have to get bigger injectors. Problably going to have to do fuel pump and regulator with it. Damn...what have I started?!?!

Coconut

At that price, I'd get an LS1 to put in it, & be ahead of the game. Of course, a superchager can always beef up a well built LT1. I just don't think the LT4 is worth the price.

Good Luck!

hgh pwr

I have done this swap on my 94 a4,it is a great kit.Had my heads ported w/hot cam you won't be dissapointed.Car ran 12.20's spinning my 315 drag radials. I did the later opti upgrade but you don't have to.no drivability problems it idles at 700 rpm's. Make sure you get a good tune,some guys say you don't need it but I think you do. header help(long tubes).good luck

Zix

Good luck! First off, if you can find a decent LS1 motor for that price you're forgetting the amount of time and $$$ needed to transplant the LS engine into the C4...it's not that easy, especially if you're dealing with a manual transmission.

If you get the LT4 conversion package, they pretty much all come with the LT4 Hotcam kit as well, which is where a lot of the extra power comes from...but also, if I remember correctly, the 425HP number was obtained with longtube headers as well.

It's a nice package that will give you a nice kick, and it's great that it's all pre-packaged and bundled together. You may be able to make a some more power if you get your heads ported and a little healthier cam though. However, the LT4 heads have more potential so if you wanted to spend some extra money down the road you could have them ported and make more power than a ported set of LT1 heads.

Also, with a couple of other little upgrades you can get the engine up to 450HP (1.7 rockers and an electric water pump will help).

Are you doing the work or would a shop be taking care of it?

rickneworleansla

Theres nothing wrong with the LT4 kit but you can get a custom cam and ported heads that will make more power for that price or less. Check here.

http://www.eportworks.com/

They can also walk you through what else is needed.

93 ragtop

If you do the heads and hotcam, you will be making more power then the LT4. The hotcam is not the cam that came in a LT4. It is a factory offroad cam designed for the LT4, but it has more lift and duration then the stock LT4 cam.
Basicially I have ported heads, hotcam, long tube headers, and you can see my results in my signature.
I am very happy with my setup, but if I were to do it again, I would look into one of the Lloyd Elliott setups. Great price and good power at a better price then the LT4 setup.

Edit to add link. http://www.eportworks.com/

BrianCunningham

Here's a good read
http://www.corvettemagazine.com/1999/oct99/lt1/ltp1.asp


Forum member Nathan Plemons LT1 build.
http://www.wku.edu/~nathan.plemons/h...rformance.html

TOO_HOTTVETTE

I have this set up and was happy with the power it made in my '93, I got the Idea from Corvette Fever magazine and I think it's the same basic article that is mentioned in post #11 above. My set up is LT1 with the LT4 heads and intake, Hotcam, 52mm TB, K&N, EM long tube headers, Meziere waterpump, Tune by PCM for Less. I am now doing a 383 and am porting my LT4 heads. I don't think the package you are looking at is available anymore as the LT4 intake is not available..I think that Edlebrock has an LT4 aftermarket intake on the market now, but I haven't read of anyone puchasing or installing one yet. The LT4 heads will only work with the LT4 intake. All that being said, you can get the same power as the advertised kit by porting your stock LT1 heads and doing the hotcam and all the other complemetary mods. The link to Nathan Plemons is a great example of what an LT1 can do. 400hp at the crank is doable and will keep you in the hunt with all the newer more powerful cars out today. Good luck.

Coconut

I still say the LT4 heads are not worth the price for the kit. Get some better aftermarket heads for that price, & then use the LT4 stuff, if you're determined to use the LT4. By the way, I know someone with an entire LS1 setup (6 speed tranny, all pulleys, ECM wiring harness, & etc) that he bought for only $1500. Everything works great. The guy needed some quick cash. It was pulled from a running car. It may take some time to find, but the deals are out there. Don't look on Ebay. Everyone buys stuff there, & the prices will get too high. Good luck with the LT4, though.

Coconut

I work at a shop that builds top fuel dragsters. If you have the equipment & know-how, it's not too bad. If you're clueless, then it can be a challenge. But, you never know what people are capable of, or who they may know that is.

Lichen

With an auto and B&B.
.
Might I suggest just the Hotcam Kit and have your heads ported. That with the longtubes and tune should give you the kick that you need.

dchildress

Looks nice. Thank you for going thru the trouble to post pic.

I notices you have the frame xbrace....did that make a big difference? How much clearance did you loose? Mine is already lowered 1.25 inches and I worry about ground clearance.

It might sound a little silly but I want to stay with an LTX motor. I don't want to go the LSX route.

It seems to be a pretty even split between GM Perf Parts LT4 kit OR HotCam and head work. I am leaning toward the GM kit, but if $$$ gets tight I will probably go the other route. Either way I need to start saving up.

dchildress

My buddy used to work at a Caddy / Chevy dealer. He is going to be doing the work for me. He was the C4 & Northstar man there and was starting to get more comfy with the C5s. He bought his brother's service center and is a big Vette fan. Plus his shop is less than 1 mile from my house. He only charged me $300 to R&R the motor in a 2000 Mustang GT I bought as a repo just to sell for some spending cash. Most of the stuff he does for me is after hours and cash only which helps keep the costs down. He is looking forward to doing the LT4 kit so he can offer it to others.


Anybody know any tuners in the Cincinnati/Lexington/Louisville area that can dyno tune this thing when done?

Lichen

Mine's a convertable and they all came with an x-brace.

Coconut

Go to the following website for several engine coversions. Note the 1987 Corvette with the LS1 in it!!!

http://efiswapshop.com/Pictures.htm

Coconut

Don't waste your time & money on the LT4 heads. Put the money into something else.