4.3 L kit

Has anyone done the bump up to 4.3 with thier SC? I am in the middle of a rebuild and was wondering if its worth it,and if it is reliable.Any feedback would be good so I can start ordering stuff

Hello? Anyone There???

What kit are you reffering to ? The only one I'm aware of is offered by Morana and it uses a cast crank from a 4.2 truck engine. I don't know anybody using the kit in a Supercoupe engine, so I can't comment on how well they hold up. I don't think the cast crank is strong enough for a forced induction engine.

Fred H. (aka Dr. Fred) had a billet crank made and Chris Wise did an offset grind on his stock crank, both are high HP heavily modded motors and between the extra stroke on the crank and boring .050 over they were about 4.3 Litre displacement. IMO, the performance gains from doing a forged or billet 4.2 crank are not enough to justify the added cost.

David

Yeah,actually that is the kit I was speaking of.They list it as a 4.3l kit though.I was just wondering if I am doing the rebuild anyways,I could just bump it up a bit.I do plan on doing alot of stuff for mods such as front IC,TB,MAF,MP blower and plenum,cam and heads.I WANT POWER!!!! I know its going to whack my bank account though Thanks for the reply.Any more info or suggestions would be great.

suprkoop said:

Yeah,actually that is the kit I was speaking of.They list it as a 4.3l kit though.I was just wondering if I am doing the rebuild anyways,I could just bump it up a bit.I do plan on doing alot of stuff for mods such as front IC,TB,MAF,MP blower and plenum,cam and heads.I WANT POWER!!!! I know its going to whack my bank account though Thanks for the reply.Any more info or suggestions would be great.

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The stock crank is forged and the one in the Morana kit isn't. Unless you are working with a very big budget and trying to build the most powerful engine in the club, I would suggest keeping the stock crank and upgradeing the rods and pistons. With a set of forged H beam rods, forged pistons and APR main bearing studs the engine will easily handle 400 rwhp. You will also want to get a high volume oil pump and a BHJ dampener and have the entire rotating assembly balanced.

I would also suggest having the deck of the block and heads resurfaced with as smooth of a surface as possible so you can use the 4.2 litre MLS head gaskets. With those gaskets and a set of ARP head studs you can run nitrous or high boost without blowing the head gaskets.

Once you have a good foundation you can add all the stuff that adds power without worry. If your bugget allows it, do the heads and cam while your rebuilding the engine. I would suggest the pagkage from Stegimeier.

David

I agree with Dave on the Steg heads/cam combo. It really is impressive. I'm pushing over 400rwhp with them.

The other thing is the bottom end. The way Dave explained it is probably the best way to go. If I could do it all over again, I would do it that way. I am currently running a stock bottom end & still exceding 400rwhp without problems. I'm also running the RPM's upto 6200. .... But I don't suggest it, because I am only about 1000 miles into whipping the sheit out of it. So I can't attest to it lasting 20k or more. That's going to take time. Shouldn't take long because I'm using it as a daily driver.

Anthony

I'm pushing over 400rwhp with them.

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Anthony,

Did you install a nitrous system or is the extra power coming from that whipple I heard you were adding ?

David

PS: You are really pushing your luck w/400 rwhp on a stock bottom end. Then again, if I had a guy like Phil wrenching on the car I wouldn't worry much either. I imagine he could swap out the shortblock in an afternoon.

I'll be getting to the big power adders real soon. I'm hoping for Carlisle. But I doubt it.

Anthony

I do plan on the steg heads and cam.I have been planning and saving for this project for about 2 years and my budget is like 7500 for everything.I've been following posts for awhile and have picked up some good info from everybody.All that dough was slated for the motor/tranny stuff but recently some little scumbag keyed my car before I had the insurance on it for the summer so now I have to repaint it and am doing alot of the body/prep work myself to save money.So hopefully I can do all my stuff and have enough money for the project to get it done for at least some of the summer to drive it.But I dont know-maybe next summer I just want to do it right the first time and all at once so I can see HUGH gains in performance.Can you recommend good pistons and rods?I do plan on nitrous in the future also(for power and I like purge valves -they're cool)

My suggestion is to get started with the Steg heads/cam ordering. That may take over a month by itself. Then also get started with the ordering of your rods & pistons. By the time you get to putting it all together, you'd be lucky to have everything in. ... During that time you can prep your car. With a ready prep'd car, it shouldn't cost more than 1k to get a nice paint coated on there.

With commitment on your part to keep on top of everyone else, you could potentially be up & running in about a month. Good Luck Man! Sound's like you could have a sick ride in no time!

Anthony