January 2012 Chevy High Performance Q&A

Kevin McClelland Nov 23, 2011 0 Comment(s)
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Engine Build (unclassified)

First of all, I would like to say I love CHP, especially Performance Q&A. I am new to engine building. A friend and I put together a ’69 big-block Chevy 396 bored 0.030-inch over. I used a COMP cam with 0.575/0.575-inch max lift and a set of Icon dome pistons, PN IC-9949.030. The pistons have a -41cc and a 0.580-inch-tall dome with a 1.765-inch compression height. I’d like to use oval-port heads, with a low intake runner number, but I cannot seem to find a set of heads that will fit without the Icon pistons hitting them. This engine is going in a ’71 Nova four-speed with 4.11 gears. What cylinder heads do you recommend, preferably aluminum? I was told I need open-chamber heads. Keep in mind, I don’t want this to be a slug. Thanks, and keep up the great mag!

SFC Kelvin D. Young
U.S. Army Battalion Motor Sergeant

A. Wow, when a question comes through as “unclassified,” we know we’re getting close. Kelvin, you guys and gals sure can think up some great combinations when you’re deployed. We’re glad to keep building parts to hot-rod your cars for when you guys come home. Thanks for all you do!

The selection of oval-port heads with open chambers is pretty slim. Brodix makes a Race-Rite aluminum head that comes in with a 270cc intake runner and an 119cc open chamber. This chamber, in conjunction with your 41cc dome, is going to kick the compression ratio to right around 10.0:1 on your little Rat. This will be perfect with your aluminum heads. These cylinder heads come equipped with 2.250 intake valves. You’ll need to make sure that the valve reliefs in the block will clear these large valves at your 0.575 inch of max lift. For more information on all the options of the Race-Rite cylinder heads, give Brodix a call at 479.394.1075.

Good luck with your project when you get home. You and your buddy have a blast with your four-speed big-block Nova! CHP

Source: brodix.com

Shifty Business

I have questions about rebuilding a TH350-C. I have everything done except the valvebody. I bought a shift kit, but things don’t line up. I think it’s for a TH350, but without the C part. I sincerely need help with this; it’s driving me nuts. Thanks for any help you can offer.

Dustin Cross
Via email

The TH350-C was released in 1980 and ran through 1986, when GM redesigned the TH350 with a lock-up torque converter. They were used to increase fuel economy. The shift kit you have is for a standard TH350 and doesn’t accommodate the lock-up converter solenoid and the appropriate passages. You need to pick up a B&M TransPak, PN 30235. This is the next step up from a standard shift improver kit. The TransPak gives you two stages to choose from. First, a standard shift improver, and the second stage gives you full control of the trans. You can hold the trans manually in any gear for as long as you wish. The trans functions normally with the shifter in the Drive position. Check with B&M for more information, or just get one on order. Don’t forget where all those little balls go!

Source: bmracing.com


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