engine help.

[Stephen717]

So I fell into a bit of luck today. I have been trying to get stuff together to rebuild a 350 from a 1992 silverado and have been trying to sell off the swirl port heads and intake since I got it. so there's a guy at the end of the road I live on that has been working on motors for years and has lived above me for about 3 years now. I asked him if he would be willing to buy them and he said that he had doubles of everything but needed a solid crank. I took him the one I had out of the motor I have been trying to research and get parts for and he told me that the block is useless (it's a cast # 727 block from a truck. He said that I would be lucky to make 240 hp with it.) but he liked the crank I brought him. It just needed cleaned up. so long story short he traded me a 350 block from a 1988 corvette that is already set up for a roller rocker setup. He told me that with the swirl port heads I could make 300 hp on this motor pretty much stock. But I am trying to make 500 to 550 hp with this thing. I already know that I want to get it punched .20 over and I would like to go with the roller rocker setup. but other than that I am very inexperienced with motors. Will an older set of heads and an older intake fit on this motor? what cam and crank should I go with? What pistons should I use? like I said I would like to make somewhere in the ballpark of 500 to 550 hp. I know that the numbers on the block are GM 5.7 LG, J267, 62, 638, 1493638, H, V1029ZMD, 1J5106238, 627, G1, but That's about all I know about it. any help would be greatly appreciated.

Thanks,
Stephen

[leftybass209]

Making 500+ HP on a sbc is no joke. I don't mean to be rude, but if you don't know the combination of parts needed to get to this level of HP, you'd be best to have a good engine shop get this done for you. Older intakes and heads are nearly out of the question to make this kind of power consistently and reliably.

Take a look at the build in this link, which uses an aluminum Dart block punched to 427 cubic inches to replicate much of what the LS7 uses to make 500+ HP.

http://www.superchevy.com/how-to/vem...-dyno-testing/

[Stephen717]

thanks for the link. I know it won't be easy but if I have the machine shop do it I will never learn how to do this kind of stuff. I know there are a lot of older heads out there that did flow really well and made power, and I know that this kind of power was made back in the day, but I didn't know if they would bolt up. And I think reliability wise if I get them ported and polished and put new springs in them they would be a practically new set of heads. I was also asking about the older heads so that it would look like it came out of the 60's even if its a late 80's block (still set up for mechanical fuel pump to). I will read the article later today and see what all they used. It might give me some ideas.

Thanks

[wbc409]

Wanting that kind of power limits you to race gas or E-85 because of the compression required. Not sure what you are planning on doing with the engine, but at that power level it is unusable on the street for 99% of people. It will require a manual transmission or a very high stall converter in an automatic. It will need aftermarket heads, and intake, preferably a roller cam, and about 12 to 1 compression. You can't cheap out on the parts either or the engine won't last. If you build it into a 383 stroker it won't have to be as radical to make that much power. Cubic inches are your friend in this case.

[67 chevelle]

you want an ls3 , not a 350 sbc ,for those numbers

[truckster]

Originally Posted by Stephen717

thanks for the link. I know it won't be easy but if I have the machine shop do it I will never learn how to do this kind of stuff. I know there are a lot of older heads out there that did flow really well and made power, and I know that this kind of power was made back in the day, but I didn't know if they would bolt up. And I think reliability wise if I get them ported and polished and put new springs in them they would be a practically new set of heads. I was also asking about the older heads so that it would look like it came out of the 60's even if its a late 80's block (still set up for mechanical fuel pump to). I will read the article later today and see what all they used. It might give me some ideas.

Thanks

It sounds like this is your first engine build. As someone who has built a lot of engines, I would respectfully suggest that you make your goals a bit more conservative. Have you driven something with 500+ horsepower? Even 300 horsepower in one of these trucks is a solid engine, but you're talking like someone who doesn't understand that what you really want in a truck is TORQUE. Aim for 300 - 350 lbs/ft of torque and I think you'll find your build is a lot more achievable and plenty rewarding.

[leftybass209]

Unless you're die-hard for a sbc, an ls can get you at that power level quicker, and at an equivalent price, but with a more steetable, fuel efficient engine. Build techniques are the same.

Learning to build an engine, how all of the parts interplay, and all of that isn't something that you learn in 1 build. Many Junior Colleges go through a basic mechanics course where you'll learn a lot, along with a tear down and rebuild of a sbc. For the price of the book,class, and working on their engine it's very worth it. Doing a serious build like you want, with no knowledge is a recipe for disaster because none of the parts are cheap. If you make a mistake, it costs possibly thousands of dollars.

[Marine-58]

For what is worth, I agree with everyone else on this. Building 500+ HP from a small block is complex and you really need to know what you are doing. Currently I am running a 383 with 465HP. It is very street-able. Going much beyond that and you will spend time tweaking and tuning. Make a mistake on what parts you put it together with and it can be catastrophic.

However if you are dead set on doing this, have a long talk with someone you trust to give you good guidance. Don't rush your research. And positively make sure you have a good machine shop. You will also need to improve your entire drive train from Tranny through Diff. The right gears can make something like this really move. The wrong gears and you have a 500HP dog.

Suspension, tires and brakes are also very important. This much power in one of these trucks and it can scoot along very well. You don't want to get in trouble hitting a corner too hot or not being able to stop.

As Truckster states, for your first build be conservative. It is easy to get mid-300's out of a SBC and it will be reliable. If you use good parts for the lower end, it would be ready for later improvements.

Certainly your call either way, just my $0.02 worth. Good Luck!!