1975 350 small block issue

[Patrick H.]

Re: 1975 350 small block issue

Where do you find this 1/2" spacer?

If I were you, and I'm not, I'd find taller aftermarket covers that look similar to the stock valve covers. That will be the simplest. For about $26 you can buy Summit part SUM-G3301 or SUM-G3301B, blast them and paint them, and no one will know. Please note that taller valve covers or use of spacers may cause your alternator to hit the valve cover if the belt is a bit on the short side. If you wish to use spacers, they are available from Summit, Jegs, etc. for about 4x the price of the valve covers.

[Joe C.]

Re: 1975 350 small block issue

Wow,
Great responses. I know I have become a heretic. But i'm not throwing my new roller rockers away. I put in a roller cam. Very mild upgrade. The rockers are roller trunnion. It is the trunnions that are too wide causing interference with the valve cover.
Two gaskets won't give me enough clearance. See photos. Rockers, oem cover, tall cover.
Where do you find this 1/2" spacer?

It was expensive and I no longer use them, but they are not for sale. If you don't mind spending 150.00+ for a set of custom made spacers, then get back to me and I will dig through my sales invoices to get you a contact. I recall paying just over 100 dollars for them, but prices have risen dramatically.

The interference should not be vertical clearance for the rocker nuts, and 2 gaskets should be enough. If the interference is because of the baffle boxes, then deform them by squeezing them to clear the trunnions.

Nothing messes up the look of a sleeper engine than the unsightly look of extra tall aftermarket rocker covers.

[Rob V.]

Re: 1975 350 small block issue

Moon Speed Equipment (Mooneyes) also sell the spacers. I have used the Moon valve cover spacers with great success on a couple of Chevy small blocks, in conjunction with the finned C-2 aluminum Chevy hipo valve covers. The spacers allow for increased valve train height, and I believe the Chevy finned aluminum valve covers do not have the baffle. FWIW. Best Regards, Rob Vanderhoeven

[Joe L.]

Re: 1975 350 small block issue

Moon Speed Equipment (Mooneyes) also sell the spacers. I have used the Moon valve cover spacers with great success on a couple of Chevy small blocks, in conjunction with the finned C-2 aluminum Chevy hipo valve covers. The spacers allow for increased valve train height, and I believe the Chevy finned aluminum valve covers do not have the baffle. FWIW. Best Regards, Rob Vanderhoeven

Rob------


If you're referring to the C2 style finned aluminum valve covers, the definitely do not have the baffle. However, those valve covers cannot be used on a C3 with C-3-style PCV system.

[Rob V.]

Re: 1975 350 small block issue

Correct on both counts Joe! Thank you very much for the clarification/correction. Best Wishes, Rob Vanderhoeven

[Ross F.]

Re: 1975 350 small block issue

Yes, the roller trunnions are wider and are interfering with the baffle. Have to say I am reluctant to simply squeeze the baffle to get it to slide past. Fearful of eventual unsqueezeing. Maybe cutting and tack welding. Argh. Nothing easy.

[Joe L.]

Re: 1975 350 small block issue

Yes, the roller trunnions are wider and are interfering with the baffle. Have to say I am reluctant to simply squeeze the baffle to get it to slide past. Fearful of eventual unsqueezeing. Maybe cutting and tack welding. Argh. Nothing easy.

Ross------


The style roller rocker arms you have, while excellent, will not work with 68+ valve covers. To work with the 68+ style valve covers you have to use roller rocker arms with narrower trunnions. Usually, these will be aluminum roller rockers although even some of these will not work. However, there ARE aluminum roller rocker arms specifically designed for use with 68+ style valve covers.

[William B.]

Re: 1975 350 small block issue

Would the L-48 and L82 intake and exhaust manifolds be the same? Looking at buying a rebuilt '78 L82 less those parts.Thanks, Bill

[Joe L.]

Re: 1975 350 small block issue

Would the L-48 and L82 intake and exhaust manifolds be the same? Looking at buying a rebuilt '78 L82 less those parts.Thanks, Bill

Bill------


For 1975, the L-48 and L-82 intake manifolds were the same cast iron manifold. However, things changed for 1978. For 1978, the L-48 had a cast iron manifold and the L-82 was equipped with an aluminum manifold.

[William B.]

Re: 1975 350 small block issue

Joe...Thanks a lot. There is an after market aluminum intake for a hundred more for the L82. Also, the '78 HEI distributor is available for $50. Is it different from the '75's? Bill

[Ross F.]

Re: 1975 350 small block issue

Dont know about the exhaust manifolds may be the same. The intakes are definitely different.

[Joe L.]

Re: 1975 350 small block issue

Joe...Thanks a lot. There is an after market aluminum intake for a hundred more for the L82. Also, the '78 HEI distributor is available for $50. Is it different from the '75's? Bill

Bill------


With aftermarket intakes, be sure they provide enough hood clearance for the air cleaner. There are a few good original L-82 aluminum intakes on eBay right now at very reasonable prices. Casting numbers are 458520 and 14007378.

The 1975 and 1978 HEI distributors are basically the same. However, centrifugal and vacuum advance is different between them.

[Ross F.]

Re: 1975 350 small block issue

Just a note to finish this thread. I bought a set of 3/8 spacers which needs two gaskets. That gave me the needed clearance.