January 2011 Chevy High Performance Q&A - Performance Q&A

Tom Truty Dec 9, 2010 0 Comment(s)
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When the heads were installed on my engine, the guy mistakenly used Fel-Pro 1074 head gaskets (LT1) instead of the correct 1003 gasket. After adding coolant and finding water in the oil pan, I pulled the heads and the lifters to clean and relube. I noticed that the cam lobes are positioned farther forward (not centered) in the lifter bores than normal. What is the correct way to install a retrofit roller in a first-gen small-block? Also, any idea on estimated power for this build? The other components are Comp Cams 26918 springs and Pro Magnum 1.6 rockers. The intake is an Edelbrock EPS with a 650 Edelbrock carb. I'm using a DUI ignition, Muncie four-speed and 3.55 posi, Hedman 15/8-inch headers with an X pipe, and Be Cool electric fans and radiator. Thanks for any help you can offer
Keith Anderson
Ft. Worth, TX

A: Installing retrofit hydraulic rollers into an early small-block is very simple. Using a Torrington thrust bearing behind the timing gear, and a thrust button to control the endplay, is the right way to go. Your question about the lobes lining up with the tappet holes is a little worrisome. Yes, they will sometimes be slightly off, but the roller wheel must be in full contact with its matching lobe, and the lobe can't be so out of line that it will hit its neighboring lifter. Our best gauge if the camshaft is lining up properly in the block is how the distributor gear on the cam lines up with the distributor tunnel in the block. This should be quite centered. The distributor gear shouldn't run off the edge of the camshaft distributor gear.

When you say you have a thrust bearing behind the camshaft gear, it must be machined for this bearing. If it wasn't and you installed a bearing behind the gear, the timing chain wouldn't line up with the crankshaft sprocket.

Checking out the Isky PN RR-265/272HYD, it is a direct retrofit hydraulic roller for '57-87 first-generation small-blocks. The cam specs out at 217/225 degrees at 0.050-inch tappet lift, 0.485/0.505-inch max lift, and is ground on 112 centers. You must have had a custom grind done for your 327 at 108 separation angle. We like the profile for your little Mouse. With the combination of components you have listed, you should see the horsepower come in at around 400. The torque is going to fall in around 375-380 lb-ft. This should give you a very nice-running package with a great idle quality. At the higher engine speeds it should sound like the late '60s all over again. Enjoy.
Source: iskycams.com

Technical questions for Kevin McClelland can be sent to him at chevyhi@sorc.com.


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