Need some expert opinions.

I have a 71' Vert with with 46K miles. The engine is rebuilt I think because someone blew it up. This is my best guess. The specific information is below.

Car is a 71' 4 speed. Base 270 HP engine. Mfd: February 1971

Possibly has a bigger cam, definitely has an aftermaket timing chain/gear.

All internals appear to be quite new. (Less than 3k on the rebuild.)

Engine Block: Engine stamp ledge is milled smooth. No numbers at all. Casting Date of Block

I 11 1 (Sept 11th, 1971) A 72' Block.

Intake: 3973469 Cast Iron. Date Code?: D 17

Heads: Left side: 3947041 Date Code: C14 70 (March 14th, 1970)

Right side: 3947041 Date Code: D19 70 (April 19th, 1970)

According to Mor-Tech, These numbers are for model years 69-70 .


Car came with smaller 6.75" Harmonic Balancer, and no timing tab.

With the smaller balancer and a new timing tab, still unable to time the car. Mark on balancer

is nearly straight up, but tab sets off to the right, when the car was timed by ear, and running quite well.

I ordered a 1971 Balancer and received an 8" one from Corvette Central.

68-71' base engines used 8" balancer. 1972 used a 6.75" balancer.


So.... The magic question is: Which balancer and timing tab should we put on this motor? If it's a toss-up, which is the better choice?

Thanks.