im gonna rebuild my engine, im doing a 355 w/11.5:1 c/r my heads are 56cc and ill be squeezing up to a 200 shot. im using my stock crank. can someone shoot me in the right direction were to buy the parts i need? i need to know what pistons, rods, rings, head gaskets. is there just a kit i can buy with everything but the crank?

 

you don't want to use the stock crank. it wont hold a hi-po 355 with a 200shot. at least not for long. unless the 355 is somewhat powerless. stock internals are rated to 500hp. msot head cam cars make around 375-410rwhp. adding 200 ponies would be risking a lot. probably even your nice new fordged rods and pistons. everybody seems to like eagle rods and crank on here. H beams would be my choice. i like the looks of the srp pistons for the cost and fact that theyh are forged. speed pro forged are not bad either.

 

You can get by with the stock crank and a lot of people do it, but with a 200 shot, you might want to at least invest in a Cola, Scat or Eagle 4340 forged. You can get them for pretty reasonable prices. Now, I would suggest good forged Manley, Eagle or Scat H beam rods along with a good forged piston made for nitrous use. Go to www.jepistons.com and you can get about all the info that you need from their site as far as the compression ratios with the JE and SRP pistons. It is a good site and it will give you info on what piston to use for the nitrous. Diamond pistons at www.diamondracing.net has some good pistons also. As far as prices, www.cnc-motorsports.com has about the best prices on pistons that I have seen, either them or www.flatlanderracing.com. King Alecular, Speed Pro and Clevite are all good bearings and Fel-Pro 1074 head gaskets should be fine.

 

Also, a good set of plasma moly rings would be good or you could even consider some Speed Pro Hell Fire rings.

 

God you guys want to over build this thing.....

The only hard part is the N2O shot..... But that can be taken care of.

The stock crank, at least the late model ones that are used in the LT1 are great cast cranks. Cast cranks fail when they develop a crack, where a forged crank can deal with it longer. If the crank was or still is running when you take it out of the block and there are no bad marks on it from a burned bearing it's probably not bad.

The big key to cranks is the radius in the corner of the rod and main journals. If there is none, then the crank is about 50-75% as strong as one that is, it's hard to gain a huge amount of strength with materials but the manufacture of a crank can cause some good results.

One of the things to see on a LS1 crank is that instead of a nice radius in the corner of the journals you see a under cut radius of 270 degs rather than a 90 deg radius. This is one reason why the LS1 crank is a strong mo fo. Those things don't BREAK!

A few things if you want the stock crank to be strong and fit for the job of what you are looking at here.....

1. A good balance job. That is going to reduce the stress on the crank a ton! I also like internally balancing the crank, so get a neutral balance flexplate or get the flywheel neutrally balanced.

2. A good balancer, a TCI, ATI or a Fluidamper balancer will extend the life of the crank even more.

3. Polish the journals.... Make sure the turn the crank the right way when doing this so the gain structure is laid down the correct way.

4. If you grind the crank undersize make sure they will dress the grinding wheel enough to put a big radius on the edge of the crank. Most shops don't do this but a good crank grinder will do this. It's normally around $50-$100 to have this done.

5. This is a odd one, but a 4/7 swap camshaft will cut down harmonics on the crank. It makes the crank last longer along with improving HP.



As for the rest of the parts.....

Mahle Pro Pack setups are a very nice way to go. Set the ring end gaps that come with the rings for the N2O and you will be doing well. They are a little beefer than the comparable SRP and work out to be cheaper than a SRP ring and piston combo. I would also look at the Diamond flat tops.

SRP is nice when you want a light weight piston but a 200shot N2O motor doesn't always need that.

For Rods I would look at the Scat I beams. A 6" I beam can definately take what you are doing, if you need insurance a 7/16 bolt Scat I beam would be the way to go.

I only have a problem with Eagle H beams on something like this because it's flat out overkill and the extra mass from them is going to stress the crank more. So you might as well take what's strong enough and hurt the crank less.

BTW if the stock internals are rated at 500hp and the only thing that fails are rods and pistons, upgrading from a hypereutectic piston to a forged piston and from a stock cast rod to a forged 4340 I beam is going to be a huge amount of overkill. No need to spend extra money on H beams and forged cranks. Spend that on the parts that make HP. Forged cranks sound good, but don't get you down the track any faster.

Bret

 

i know i said up to a 200 shot but, ill probably never go that big. ill run 125 jets most of the time and probably do a 175 on occasion.

should i get flat top or dished? whats the diff?? what cc piston and what size head gasket will i need to get the right compression ratio

i forgot to mention but this is a budget rebuild and thats why im using the stock crank

 

Flat tops!!!!!

Zero deck the block and run a fel pro gasket. Can't do it better than that.

Bret

 

ur stock crank is fine...

get flat pistons, u want ur cr higher than what dished pistons would give you...

not sure bout the headgasket, i have felpro1074, but they are sorta thick (good for fi) u can find out about cometic gaskets, they are thin so it'll keep ur CR higher...

 

why?? i dont know much about internals, can you fill me in. are all flat top pistons gonna give me the same c/r it the block is zero decked? what is zero deck? would i even be able to get 11.5:1 with a dished piston?

 

Most dished pistons are going to kill your compresion ratio stupid fast!

The zero decked block will make the quench area perfect with a Fel Pro gasket. Zero Deck, means that the pistons come up flat with the deck surface at TDC. This way will get you less detonation and more power, two very good things in engine building.

Bret