Gentleman,

I've spun a bearing and I've searched til my head hurts.

Details: 95 Impala SS 350 LT1
Stage 1X Combination Motorsports top end (iron heads)
Cam: CC Extreme 218-230 114 LSA
Intake: .495
Exhaust: .510

Intercooled ATI P-1SC (8lb).

Bearing scars on crank so I'm thinking, time to stroke her. The question is: What are the advantages of 355 vs. 383 vs. 396 vs. 409?

I'm leaning towards the advice of:
JE/SRP pistons
Forged Eagle H-Beams 4340 (5.7")
Forged crank 4340 (1 piece rear main seal/375 stroke)
..and 4 bolt splayed and main studs. 383.

My goal is to have a street car with the ability to flex some nuts at the track and pass emissions (OBD1). Again, more street than track. Do you think my cam is too small or perhaps a new one.......224/236 115 LSA?

What do you think, guys?

Edward

 

>I would contact www.cmotorsports.com ask Seth for his recomendation .
I would go with the 409 (how do you get that ? ) and Oliver rods instead of the Eagle for more clearance and less of a chance of using different size cam diameter (I believe) that is the reason I went with Oliver instead of the Eagles .


Also when you spun your main bearings did it make a "wurring" sound ?

 

No, tapping/ticking.

Actually the rotating assembly listed was suggested by Seth. Unfortunately, my wallet may be the weakest link. Hence why I didn't go with Oliver rods.

Any other options?

Edward

 

383

396 and a 409 would have aweful rod to stroke ratios which in turn is hard on cylinder walls. A 383 is plenty of cubes for a blown motor, and will be cheaper too since you wont need a small base circle cam to clear connecting rods.

 

how much power do you wanna make? honestly? if its <700hp, get a scat 383 crank, eagle h beam rods and some SRP pistons.


the extra cubes for a 396 are nice, but not worth the big jump in price. if you are going to run a forged crank anyway, might as well go with the 396 tho.

 

I'm thinking 500-550 @ the wheels will suffice? I'm not worried about trying to squeeze everything out of her.

I opted for:

- Eagle 4340 forged steel crankshaft

- Eagle 4340 forged H-Beam connecting rods

- SRP forged pistons .30 over

Anything else I should tackle while it's all apart?

I appreciate your suggestions!

E

 

Your list will net you more than 550 rwhp if you turn up the boost a bit.

 

I'm actually in the process of building almost your exact combo.

I have an Eagle 4340 3.75" stroke one-piece rear seal crank.

5.7 Eagle H-beam rods with L19 bolts. I've heard that the stock Eagle bolts aren't very good.

I have a set of SRP 31 cc dish pistons.

I've used these rods and SRP pistons before and had very good luck.

I'm using Program steel straight 4 bolt main caps.


The larger displacements necessitate longer rods. The longer rods and stroke push the piston pin higher in the piston. This means that you have to cram the rings into a smaller space making the ring lands thin and fragile. That's why I chose that same stroke and rod length.

Also, a 5.7 rod will build more low-end than a 6.0 inch rod. I think that this will work well with the top-end rush of the centrifugal supercharger.

Mike

 

I don't know what rearend you have in your car, but you'd be wise to upgrade your driveline along with that motor. The stock 10-bolt (if you're still running it) doesn't deal with 450rwhp+ very well. Especially if you put sticky tires on there. Just an idea for you to think about.

EDIT: I just realized this was an old post. What setup did you wind up going with?