Engine build

[Guest Anonymous]

I'm building my 350 (An l-42 out of a 79

corvette) for more power.

 

I was looking around, and I found the Holley

SysteMAX II kit for 1300 bucks.

It looks like a good deal (heads, intake, lifters,

cam, push rods, ARP head bolts).

Holley claims that it makes 425 HP with a

compression ratio of 10-1.

 

But Holley's web site also says that the kit 'requires' Lunati rods, pistons, and crank.

 

Now its my understanding that you'd only want them if you planned to rev the bag out your motor.

If you just go to stock redline, then could the

systeMAX system be used with stock crank and rods?

 

Greatly improved intake/exhaust flow from the kit couldn't make stock type rods and crank (and maybe pistons?) unusable could it?

 

Also, I know that higher compression ratio means higher power, and higher octane requirment.

 

I'm condidering rebuilding the short block with a northernautoparts.com street performance kit. But the flattops with the 64cc heads will make about a 10-1 ratio, right?

And reverse dome (dished) pistons (like came stock) will make about a 9-1, right?

 

So which would be a good choice for a daily street driven vehicle? The lower comp ratio would make pump gas run better, but the 10-1 would make better power. But will 10-1 run on pump gas?

 

Either way I'll be rebuilding the short block, but I'll be getting hypereutectic reverse dome pistons rather than flattops if I decide to go with the 9-1 compression ratio.

[Tim240z]

Jack,

As long as you aren't going to RPM the heck out of the motor, the stock cast crank and rods will live forever at 6000rpm and less. Just make sure that what you start with is in good shape. Also 10:1 compression with aluminum heads will be OK with premium pump gas. If the heads are iron, that might be pushing it a bit, but should be OK, depends on the cam.

Others here will probably be able to give more specifics, but here's a first stab.

Tim

[DavyZ]

You can use the stock crank and pistons, but you are assuming a couple of things here:

 

1) They (rods & pistons) are up to handling the new power (as memory serves me, stock rods are good up to about 400 hp or so.

 

2) the 425 hp you make is still in the 'safe' rpm range for your engine with the stock bottom end. If the 425 hp comes in at say 6100 rpm like they say it does, you should be alright, at least for a period of time. How worn are the rings and bearings? Grumpyvette or one of the other experienced guys would be able to tell you best.

 

Keep in mind that the Systemax kit probably works 'best' with forged pistons and quality rods, because Holley owns Lunati and they want you to buy the stuff. Seriously, if you bottom end is new like the top end, then you'll have a motor that will live longer, especially with drag strip abuse and the like.

 

The Systemax kit is good bang for the buck IMO. Even if you didn't keep the intake manifold, you could always sell it and recoup at least $100 on ebay for it--seems like many people pay too much for junk, so I wonder what they will pay for a new quality piece?

 

Davy