Northstar + supercharger

[cpk]

Dad and I were talking over the holidays about his plans for his '65 Skylark (has a 401 nailhead).

There aren't many performance parts for the stock engine. An easy route would be to get a big-block Buick engine and drop it in.

However, we were talking about the possibility of a supercharged Northstar. The Nailhead weighs in at almost 700lbs, while the N* is closer to 450. He'd be running an aftermarket controller, so tweaking the stock PCM is not an issue, and he'd probably end up with either a T56 or ZF out of a Camaro/Firebird/Corvette.

We were just wondering how much boost the bottom end of a stock (but rebuilt) Northstar could take for regular street driving and the occassional weekend drag without having to do any serious modifications to the rods and/or crank. For that matter, at what point would we have to worry about the heads sealing?

We were thinking of utilizing one or two Eaton M60 superchargers that GM uses on the 3.8 (depending on the amount of boost), mostly because they're plentiful, relatively inexpensive, and have a long service life. We figured that if the stock M60 can support a 3.8, then two M60s with oversize pulleys (running slower than the 3.8 uses) would support the 4.6 without having to work too hard. Perhaps slowing down the M60s would negate the need for an intercooler?

[Bruce Nunnally]

Definitely check with chrfab.com as they do a lot of this sort of thing, northstars for hotrods.

[cpk]

I'll have to give them a call. Their site's not very informative.

I did find an article in Hot Rod which discussed the N* and chrfab:

"The OE main bearing caps are sufficient. Even at the 500-plus horsepower level, the stock cylinder block requires virtually no modification, and at this stage, the engine will reliably and repeatedly sustain a crankshaft speed of 8,500 rpm.

"

(This is after chrfab balances and preps the block, ports the heads and uses their cams)

and (with regard to the connecting rods)

"Johnson prefers the early-model rods for applications up to 400 hp, but has used the late-stock rods in his own blown motor. With boost to 7 psi, any rods will work, but beyond 10 psi, he prefers the Crower forgings."

FWIW...

[JasonA]

The Northstar is an incredibly strong engine. In fact, it doesn't use separate main bearing caps, like traditional engines use. It's a full crankshaft girdle, that uses 20-25 bolts (can't remember the exact number) that bolt it, and the crankshaft, in place. Much better than separate bearing caps. Puts the vaunted "4 bolt main" Chevy engines of years ago to shame.

[cadillac_caddy_sts]

Definitely check with chrfab.com as they do a lot of this sort of thing, northstars for hotrods.

Thats A great site Bruce I was on there a minute ago lots of info on it.