Next, with the crankshaft change in '86 to a one-piece seal design, it also changed the crank-flange bolt pattern to an externally balanced flywheel/flexplate. You'll need to go back to a two-piece flexplate PN 471529.
Ed, the 350 block has the same external dimensions as the 305 and will bolt right into your IROC with no modifications. As we said in the first answer, one of the best parts is that the smog police won't even know that the long-block has been touched.
Ken's Going To Hate Me!Q I have a '69 Chevelle 383 stroker, a TH350 trans, and a Moser differential with 3.73:1 gears. The speedometer is way off and reads much faster than I'm going. My mechanic tells me that he cannot change the gears in the trans to compensate. Where can I find more info on this? Thank you very much.Scott HippertDover, MN
A Years ago I had another reader write in with a speedo calibration problem. Well, I recommended then that he contact Ken Casey at Burt Chevrolet. Ken is the GM Performance Parts manager and is a wealth of knowledge. Your mechanic is off in left field. You can change out the drive and driven gears very easily on the TH350 trans. To make a long story short, Kenny sold a ton of speedo gears and gear reduction boxes to calibrate speedos all around the world. Give Ken a call at 800.345.5744, and he'll get the pieces in the mail to calibrate your speedo.
Nasty, Wicked & Wild 327Q I'm currently building-or trying to build-the most wicked, bulletproof Saturday-night-special 327 small-block for my '65 Chevelle. I need a little help ensuring all the parts I'm slowly putting together for this build will work the way I hope them to. Here is what I have so far: a casting number 3970010 four-bolt main 350 block from a late-'70s truck, a number 4672 forged (supposedly) large-journal late-'60s 327 crank turned 0.020 inch under, Scat forged/bushed 5.7-inch I-beam rods, and Speed Pro flat-top hypereutectic pistons. I'm planning on buying a set of AFR 190 heads, and fitting them with a set of 2.02/1.60-inch titanium intake/exhaust valves complete with locks and retainers that my friend got for me at a ridiculous price, a large Comp Cams hydraulic-roller cam and lifters with 1.6 Pro Magnum rockers, an Edlebrock RPM Air Gap intake, a Mighty Demon 650-cfm carb, a TH350 with 2,500-2,800 stall, and a 4.10 posi-fitted 8.2 10-bolt with a Gear Vendors over/under unit. Whew.
What I'm trying to accomplish is 475 hp and 400 lb-ft of torque on 94-octane pump gas. My titanium friend did custom-port development for Roush Racing for six years, and he is going to feather in the CNC'd ports and chambers on the AFRs, along with milling them to about 58cc chambers. I'm trying to get to 10.5- to 11.0:1 compression with the flat-top pistons so I don't mess up the quench on those beautiful heads by stuffing an ugly dome into them. Can that be accomplished with angle-milling the heads and decking the block? Is that carburetor going to be the right size? Will that four-bolt block and 327 crank be compatible (both two-piece rear main)? I'm going to have the rotating assembly balanced since I'm guessing the peak horsepower range will be over 7,000 rpm. I was told the hypereutectic pistons will handle up to 500-plus horsepower. What cam would you recommend? The block is still at 4.00 inches but is going to get machined. Any special things I should make sure the machinist does? I know it's a lot to digest, but I've done a lot of reading, and I think I can finish this build for $5,500. Please help all you can. Thanks.Matt A. SpradlingDetroit, MI