High Tech 327 Update

[Patrick H.]

Hello all,

As promised, a little update on the project.

To review, we have a 1966 never-run block, that unfortunately had a cylinder scored by a student in shop class 30 years ago. It is presently undergoing an .030 overbore, but otherwise is stock 2-bolt. The induction is 1965 off-the-shelf fuel injection unit and intake. The exhaust manifolds will be 2.5 inch new GM castings, with 2.5 inch exhaust leading to Under-the-car sidepipe-style mufflers. Exit will be ahead of the rear wheel of our 1960 Corvette.

To date, we have the pistons (hypereutectic SpeedPro H660, flat top with 2 valve reliefs), as well as all ARP fasteners, FelPro Performance gaskets, and Clevite77 bearings.

On order is a FederalMogul retrofit roller cam, lifters and pushrods, part 1070R with 210/215 duration and .462/.470 lift, with 110 degree lobe separation.

Our latest question is regarding cylinder heads. We wish to use an aluminum head with 64cc chambers, which should give us good compression as well as heat management. Exhaust crossover is not necessary as the fuel unit doesn't need one. Possibilities include Trick Flow, Edelbrock Performer RPM, or possibly Airflow Research. Some investigating reveals through other discussion boards that the Trick Flows do not enjoy a stellar quality reputation. The Edelbrocks seem to be without complaint especially for a street motor. The Airflows are very good, but also quite expensive when compared to the other two.

Does anyone have any further thoughts or experiences with any of these heads? Recommendations? You may write to me off-board if you don't wish to make your comments known.

Also, any thoughts on aluminum water pumps? As long as we're using so much aluminum, we thought this was a natural too.

Thanks for the assistance.

Patrick Hulst

[Joe L.]

Re: High Tech 327 Update

Patrick-----

Excellent cam selection. I think that it will be just what you're after. As far as water pump goes, definitely use the aluminum versions. I have been very satisfied with the Weiand aluminum pump. But the Edelbrock is fine, too. Or, go with the GM pump, GM #14011012. Whichever pump you use, check first to make sure that it uses a 5/8" pilot shaft. The Weiand does and I believe that the Edelbrock does, but I'm not sure about the GM; it might use the 3/4" pilot. This only matters, though, if you are going to use an original pulley system for a 1960. All pre-71 Corvette water pump pullies use a 5/8" pilot hole and "small" hub bolt pattern. 1971 and later pullies use the 3/4" pilot and "large" hub bolt pattern. The hub bolt pattern is not an issue, though, since all of the pumps have dual pattern hubs.

Also, although you don't absolutely need to with the Federal Mogul austempered ductile iron roller cam, I'd still recommend using the GM #10456413 melonized distributor drive gear.

[Patrick H.]

Re: High Tech 327 Update

Joe,

As you had recommended earlier, we are also going to be ordering the distributor gear.

For some further info, I guess we will lean toward the Edelbrock heads, unless I can find a less expensive source (than what I can find now) for Airflow Research heads.

An interesting note about the Edelbrocks: their information states that you must use pushrods .100 inch longer than stock with these heads. Might you know, Joe, if we have to return the pushrods that come with the FM cam, and get longer ones? I'm not sure that the people at Summit will know the answer to that one. As the cam is special order, I'm not sure what would happen.

Patrick

[Joe L.]

Re: High Tech 327 Update

Patrick-----

This situation could represent a slight problem for you. I wasn't aware that the Edelbrock heads required push rods that are .100" longer than stock length.

The push rods that come with the Federal Mogul cam kit are a special length, as are all push rods used with any retro-fit roller cams. These push rods are shorter than stock to compensate for the longer lifter length. However, they are designed to work with engines origianlly equipped to use stock small block push rod length. The bottom line is, if you use the retro-fit roller cam and lifters and the Edelbrock heads, I would say that you will then need to get pushrods that are .100" longer than the ones which come with the Federal-Mogul camshaft kit. Since the pushrods are part of the kit(if you've ordered the camshaft and lifter kit as opposed to individual components) I don't think that you'll be able to return the push rods. You'll probably have to order a set of custom lenth pushrods, which are available and actually not too expensive.

But, I wouldn't order the push rods when you decide on the heads. Your best bet would be to wait until you have the engine assembled, with the heads torqued in place. Then, using a test-only adjustable length push rod and a Manley push rod length checking gauge(Manley #42137)available from performance engine suppliers, you can determine the EXACT length push rods which the engine ACTUALLY requires. This is precisely what I'm going to do with the ZL-1.

[John H.]

Re: High Tech 327 Update

Patrick -

I've used three sets of the Edelbrock Performer RPM Chevy heads in the last four years, no problems, no complaints from eventual buyers of the cars/motors. Extra pushrod length is due to added deck thickness (unique to the Edelbrock heads vs. all the rest); my Manley gauge said they were right, and Summit had the .100"-longer pushrods I needed (Crane). Also used Edelbrock aluminum water pumps - no leaks, no problems. John

[Patrick H.]

Re: High Tech 327 Update

John,

Thanks. We'll probably still need custom length ones if we go with the Edelbrocks, as we've got the roller cam. Any comments on other brands?

See you in a few weeks?

Patrick

[Bill Baird]

Re: High Tech 327 Update

I'm running the G.M. aluminum water pump on my '75, and it indeed has the 3/4" shaft.

Bill Baird

[Bill Baird]

Re: High Tech 327 Update

I'm running the Edelbrock Performer RPM heads (70cc chambers, straight plugs) on my '75, and I think they are a very good set of heads. I bought them a couple of years ago, and at the time, they were NOT stating that you needed longer than stock pushrods, and so I'm running stock length pushrods. No problems so far, though I'm running Comp Cams 1.52 ratio roller tip rockers rather than stock rockers. Still, it makes me wonder if I should upgrade my pushrods. I rarely ignore the advice of the manufacturers. I figure they know more than I ever will about their products.

Bill Baird

[John H.]

Re: High Tech 327 Update

Patrick -

Can't comment on the other heads - have never used them or heard any commentary from those who have. I've also used the Comp Cams Magnum roller-tip rockers on every engine I've built since 1994, have had no problems or complaints with them (used on four Chevys with Edelbrock heads and three Ford 351 Windsors with World Products iron heads). I'll be at the annual Cauley extravaganza on the 10th and 11th - they asked me to bring my '57 for display (unless we're up to our armpits in snow). Can't make the seminar in Holland - just sold my house, have to keep watch on all the finishing work on our new one - the "garage with the attached house", as my wife calls it.

John