28 oz inbalance, or not??

nielsmobers · 03-21-2003, 11:03 AM

I have a '72 with a 302/FMX combo (seems to be a rare combo). Does anyone know the inbalance of the flex plate?? I properbly have a flex plate of a 351 engine (because my engine vibrates), but to be sure I have to know if there is a difference in inbalance between these two. If there isn't than that can't be the problem!

Shaggy · 03-21-2003, 12:22 PM

If you are sure it is a 72 then it is 28oz just like the 351. So that is not the problem. How does you harmonic balancer look?

nielsmobers · 03-21-2003, 04:16 PM

I've already replaced the balancer, so that is not the problem...
But your sure that if I replace 302/FMX flex plate for a 351/FMX flex plate it's the same?

Shaggy · 03-21-2003, 05:47 PM

Yes as long as you are sure you have an early model motor someone correct me if I am wrong on the year but the 302 did not become 50oz imbalance until 84(it was in the mid 80's, I think the exact year was 84). Up until them all small blocks were 28oz with the exception of a very few that were neutral balanced such as the Hi-po 289's.

mustangII460 · 03-22-2003, 01:07 AM

Rule of thumb. Gray block, 50oz. 1982 & up.

03-21-2003, 11:03 AM	#1
nielsmobers Registered Member Join Date: Jul 2002 Location: Holland Posts: 28	28 oz inbalance, or not?? I have a '72 with a 302/FMX combo (seems to be a rare combo). Does anyone know the inbalance of the flex plate?? I properbly have a flex plate of a 351 engine (because my engine vibrates), but to be sure I have to know if there is a difference in inbalance between these two. If there isn't than that can't be the problem!

03-21-2003, 12:22 PM	#2
Shaggy Registered Member Join Date: Feb 1999 Location: Houston,TX Posts: 466	If you are sure it is a 72 then it is 28oz just like the 351. So that is not the problem. How does you harmonic balancer look? __________________ A good plan, violently executed now, is better than a perfect plan next week. George S. Patton, General (1885-1945)

03-21-2003, 05:47 PM	#4
Shaggy Registered Member Join Date: Feb 1999 Location: Houston,TX Posts: 466	Yes as long as you are sure you have an early model motor someone correct me if I am wrong on the year but the 302 did not become 50oz imbalance until 84(it was in the mid 80's, I think the exact year was 84). Up until them all small blocks were 28oz with the exception of a very few that were neutral balanced such as the Hi-po 289's. __________________ A good plan, violently executed now, is better than a perfect plan next week. George S. Patton, General (1885-1945)

03-22-2003, 01:07 AM	#5
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Rule of thumb. Gray block, 50oz. 1982 & up. __________________ Frank

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03-21-2003, 04:16 PM	#3
nielsmobers Registered Member Join Date: Jul 2002 Location: Holland Posts: 28	I've already replaced the balancer, so that is not the problem... But your sure that if I replace 302/FMX flex plate for a 351/FMX flex plate it's the same?