What longblock should I use for blower
Thread Starter
Instructor
Joined: Mar 2006
Posts: 109
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What longblock should I use for blower
I have a 79 with a 6-71 dyers blower runnin 6 lbs boost (check my pic) when I purchased this the prev owner had no idea what the internals of the sbc was. I did a little investigating and I place the build at 10-15 years ago based on some of the fasteners. I have looked under the valve covers and the valve train shows screw in studs and guide plates so the heads are not stock. Also their is no harmonic balancer (shocking I know) I was told they used to not put them on blower engines because of the rapid acceleration? whatever 
SO I'm contimplating either a rebuild of this block or buying a longblock from someone (crate motors rule 
) So what size (383 or up) compression should I do? I don't want to ruin the driveability or break stuff. I raced my cuz who has a ls1 vette motor in a 96 firebird vert that has engine mods heads, cam, good exhaust, and 410 gears I plucked him.... barely! His best run was 13.01 at 1/4 mile I can probably throw $5000 into the motor oh yeah I think the carbs are 600cfm. I've actually thought about throwing on the nitrous and waiting til this motor pops 
SO I'm contimplating either a rebuild of this block or buying a longblock from someone (crate motors rule ) So what size (383 or up) compression should I do? I don't want to ruin the driveability or break stuff. I raced my cuz who has a ls1 vette motor in a 96 firebird vert that has engine mods heads, cam, good exhaust, and 410 gears I plucked him.... barely! His best run was 13.01 at 1/4 mile I can probably throw $5000 into the motor oh yeah I think the carbs are 600cfm. I've actually thought about throwing on the nitrous and waiting til this motor pops
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
with 6 pounds of boost you can get by with a stock engine. The boost won't hurt parts, it is the rpm that does the motor in.
Stick with one power adder, forget the nitrous. If you want a bigger motor then build a short block or buy one and add your top end. Heads make a big difference with a blower so if you can afford it go with the biggest heads you can afford. The blower will take care of bottom end torque. It is all about flow and with a blower go big.
You also might find getting rid of the 410 gears actually improves driveability. The blower likes to pull and with the 410 gearing you are forcing it to rev quicly through a gear and not letting the torque pull you along.
I found my car alot better off the line with 308's then with the 411's that I pulled out.
Stick with one power adder, forget the nitrous. If you want a bigger motor then build a short block or buy one and add your top end. Heads make a big difference with a blower so if you can afford it go with the biggest heads you can afford. The blower will take care of bottom end torque. It is all about flow and with a blower go big.
You also might find getting rid of the 410 gears actually improves driveability. The blower likes to pull and with the 410 gearing you are forcing it to rev quicly through a gear and not letting the torque pull you along.
I found my car alot better off the line with 308's then with the 411's that I pulled out.
Melting Slicks
Joined: Sep 2004
Posts: 2,412
Likes: 3
A 96 trans am with an LS1? Unlikely, it was probably an LT1. I can't see doing that much work dropping an LS1 into a 96 when you could buy a 98 with an LS1 stock. And just barely faster with a blower? 
Sounds like you need a much better longblock. I really have no experience with blower engines, but I'm guessing you'll want all forged internals, 8-8.5 compression, ARP fasteners, 4 bolt main caps/ block, and some nice heads. 220s or something big, I'm partial to AFR. I would go with a 383 SB (3.75 stroke crank 350 block) or a 396 SB (3.875 stroke crank 350 block) or a 406 SB (400 block) I like the 350 blocks because the siamesed cylinder bores scare me. But lots of guys around here seem to have success with them, so...
Oh yeah, smaller pulley and up the boost. Blown vettes need to run 11s, at least. It's in the Corvette Bible.
Sounds like you need a much better longblock. I really have no experience with blower engines, but I'm guessing you'll want all forged internals, 8-8.5 compression, ARP fasteners, 4 bolt main caps/ block, and some nice heads. 220s or something big, I'm partial to AFR. I would go with a 383 SB (3.75 stroke crank 350 block) or a 396 SB (3.875 stroke crank 350 block) or a 406 SB (400 block) I like the 350 blocks because the siamesed cylinder bores scare me. But lots of guys around here seem to have success with them, so... Oh yeah, smaller pulley and up the boost. Blown vettes need to run 11s, at least. It's in the Corvette Bible.
