Hey Folks...what is the size of a stock harmonic balancer on a 91 305 TPI? Was on summit and see them anywhere from 6 to 8. I'm not sure how to measure it, the ID is about 7 inches and OD in almost 8 inches.
What to keep it stock size!
Tks Troy

 

Measure by OD.

Should be about 6¾".

 

Tried to take a sensible pic..looks like 7" on the ID and 8 on the OD"
http://postimg.org/image/ctjjpg2kj/
http://postimg.org/image/c5ap6i3ur/

 

EDIT: that's the crank pulley you are measuring in the pix

TPI cars should have the smaller balancer, sounds like you have a truck or big car balancer on there. That means the timing cover has been modded or is wrong.
Maybe the motor is from a big car or truck?

 

Hahaha yes it is the crank pulley! It is a stock motor...I needed to order the timing tab actually and was wondering the size of the stock H.B. as the timing tabs come in all different sizes in relation to H.B. sizes.

 

The TPI timing tab is welded on and is in about the 2 or 3 o
clock. (please correct if wrong)
the balancer is 6 and ?

 

Yep it is a part of the timing cover, but its gone on mine. I had the block changed back in the early 90's as a warranty replacement after a cylinder wall failed. Just did the Edelbrock Hi flow baseplate and runner upgrade and got no timing marks to set up by.

 

Pull out the number 1 plug and you can find TDC with a piston stop.
Use the balancer to mark the timing cover to get you close.

Or bolt on some cheesy chrome
http://www.summitracing.com/parts/mi...FTMiMgodYBAAQQ

 

Timing tab should be at 12:00 and there are no tabs you can buy to mount there AFAIK.

 

OK some good info! Tks all!! I have hauled this from other posts:
The one with 8" balancer is TDC just past 12 o 'clock.
The TPI with 6 3/4" balancer is nearer 1 o'clock .

 

That's TBI

TPI no, its farther over.

 

Yes, from what I understand, digging deeper and learning more, is that TPI is more to the 1:30 position as you would never get a timing gun from the 12:00 position. sound right?