Pushrod Length - 72 LT-1

[Scott S.]

Does anyone happen to know the stock pusrod length for a '72 LT-1. Just finished installing a stock cam and lifters (was hydraulic) and want to validate that I have the right pushrods.

Thanks.

[Duke W.]

Re: Pushrod Length - 72 LT-1

A "stock" LT-1 cam is a mechanical lifter type and uses the same length pushrods as all other SBs, but if guidelplates are installed, the pushrods must be hardened along the entire length.

The nominal OA length is 7 25/32".

My '77 P&A catalog only shows one pushrod, 3796243 for all 55-78 small block engines. This is an old, pre-LT-1 part number, so it must have been upgraded to full hardening along the length to be applicable to those OE engines that had guildplates, which includes the LT-1.

The various OE replacement brand web sites should allow you to cross reference the above part number to their current replacement number.

Duke

[Joe L.]

Re: Pushrod Length - 72 LT-1

A "stock" LT-1 cam is a mechanical lifter type and uses the same length pushrods as all other SBs, but if guidelplates are installed, the pushrods must be hardened along the entire length.

The nominal OA length is 7 25/32".

My '77 P&A catalog only shows one pushrod, 3796243 for all 55-78 small block engines. This is an old, pre-LT-1 part number, so it must have been upgraded to full hardening along the length to be applicable to those OE engines that had guildplates, which includes the LT-1.

The various OE replacement brand web sites should allow you to cross reference the above part number to their current replacement number.

Duke

The 3796243 is a pushrod with hardened tube section. It was initially released for use on 1962 340 and 360 horsepower Corvette engines. Although these engines did not, of course, use guideplates, for whatever reason GM elected to use hardened pushrods.

In October, 1963, the GM #3796243 replaced the GM #3817616 which was initially released for all other 1962 small block applications and was non-hardened. The 3817616 had replaced the GM #3837152 which had been used since 1956 for all small block applications (yes, that's not a mis-type or an error: a pushrod with part number 3837152 had been used since 1956).

The GM #3796243 was used in PRODUCTION and SERVICE for all small block applications through the 1984 model year. For 1985 (and, possibly very late 1984), a new pushrod was used. This is GM #14095256. This is a welded ball-type pushrod, and it's a very high quality, PRODUCTION-validated piece. In June, 1984 it replaced the 3796243 for SERVICE of all 1955-84 small block applications.

For Corvettes, the 14095256 was used through the 1986 model year. For the 1987 model year, Corvette small blocks began using roller hydraulic lifters and the pushrod length was reduced to 7-1/8".

[Scott S.]

Re: Pushrod Length - 72 LT-1

Thanks a bunch guys!