Need help with a blower cam

Old 02-13-2008, 03:31 PM
  #1  
jackbn
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Default Need help with a blower cam

BBC 454 .030 over, GM 291 heads (flow 310 intake 220 exhaust), TRW L2453F, GM tufrided steel crank 10/10, Weiand 8-71. I want to get at least 10lbs boost for an occasional street driven but mostly strip car. Car is a 69 Camaro (3500lbs with driver), 4:33 12 bolt, 11.5 - 28 inch slicks. Th400 trans with brake, 3800 stall converter. I can't decide what cam to put in it, the heads are prepped for a solid roller up to .700 lift but from what I'm reading I don't need to go that big. I'd like to see a good power curve up to 7000 RPM but every "Blower" cam I've been reading about tops out at 6000-6500 RPM. Help me PLEASE !! :?:
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Old 02-13-2008, 03:43 PM
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OneBadGMC
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You're also going to need to change the rear end gears to something numerically lower. Either 4.10s or 3.90s.

I used to run a Crane Mechanical Commander, .648/.669 with the combo you had below, with an 8-71. It ran consistent 9.60s with a mere 12 PSI and 9.5:1 compression in the GMC when it weighed in a 3700 Lbs.

I used to shift it at 6800, but I can't remember what it was going through the traps at.
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Old 02-13-2008, 04:00 PM
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jackbn
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Ok, I need to ask you, why the 4:10's or 3:90's ? Also, which would be better, a 1050 dominator(9375) or 2-750 Dbl pumpers ? One more, I really don't want to cut the heads or the block for o-rings, what is a good head gasket ? Thanks for you help. The crane cam you mention is just about where I want to be.
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Old 02-13-2008, 04:24 PM
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OneBadGMC
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Forced induction makes gobs of torque. If you don't load it down, it won't make as much power.

It'll also make so much power with a higher numeric gear that it'll be harder to get it to launch without blowing the tires off.

I'd run a pair of 1050s on it, if you can afford it. If not, run the biggest (950?) of the HP Holley series. You can not put too big of a carburetor on a blower, but you can put too small of one on. Too small of a carb will put excessive vacuum on the emulsion tubes, which will make it much harder to tune and empty out the fuel bowls much faster than required.

Hell, 12 years ago when we were running the old motor, there wasn't a darn thing special about it. It was a 5140 crank, L-88 steel rods, and I think the same pistons you have with a 119CC open chamber rectangle port. We were just using stock Fel-Pro BBC head gaskets. Nothing special at all.

If you go to my website (www.onebadgmc.com), Videos 1/2 were with oval port GM heads (049 castings), with a 1020 CFM Gas carb. It was running mid 10s with 7 PSI.

Vids 3/4 were with my home brewed mechanical injection, made from Enderle/Hilborn parts. That was with the rectangle ports and 12 PSI on alky.

At that point, the truck weighed 3700ish pounds.

Passes 1 through 3 and "Boom" were with the tube chassis (3450 Lbs race ready with me in it), and my 505 with an Enderle Buzzard hat, 11.5:1 compression, 22 PSI, 10-71, and the same rectangle ports off my 462. The 505 dynoed at 1200 HP at 18PSI with the old 8-71. I have no clue how much power it made at 22 PSI with the 10-71, but it ran pretty damn good until I leaned it out and blew a cylinder wall out.

This year we're moving up to a 568, with a 14-71 SSI blower, Dart 360 heads, and a magical Jim Oddy .820 camshaft. Oddy's says no BS it should make 2000-2100 HP if properly tuned.
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