Flywheel size vs Bellhousing

[reeltales]

I have a 71 C10 that I am converting from the 250 I6 to a 327 sb. I plan to use the I6 motor mounts and Bellhousing. The original tranny was a 3 on the tree which is being changed to a Muncie M20. The clutch disc that was in the truck is a 10". I would like to go to the 10.5" or even an 11".
The question is will the I6 style Bellhousing be able to use the larger Flywheel and still allow the starter to bolt to the Bellhousing? Are the larger Flywheels the same diameter and just have the pressure plate holes drilled in a different spot?

[reeltales]

I did check my current flywheel is a 168 tooth 14", not sure if that will help with answers. Or would I be OK just to find a new 10" clutch? they see to be harder to find.

[Grumpy old man]

I just did mine recently , originally a 6 I changed the 6 cross member to the V8 so I could mount the V8 in the front holes and still use the 67 bell housing to mount a M-22 Muncie . I used all new parts from Summit . 11" clutch , You need to double check the input hole on your bell housing to make sure it matches the input size of the M-20 you may need a spacer to have a good fit . you can't rely on just the mounting ears for support , Mucie's are famous for the ears cracking without the proper bell housing to trans clearance .


https://www.summitracing.com/parts/PIO-FW100

https://www.summitracing.com/parts/PFT-MU5473-1B

[reeltales]

Looks great. I was under the impression that if you moved to the front frame holes and changed the crossmember, you would have to also change Bellhousings. Does the new v8 crossmember mount a few inches in front of the old I6 which was removed?

[Grumpy old man]

yes the V8 cross member fits the frame further forward , many guys just use the 6 position to drop a V8 in it's the fast / cheap way out . If you just want to have a V8 to go blasting around in it's fine . To go V8 correctly you'll need a cross member , drive shaft , engine perches , a better radiator , a fan shroud , and if you want to do it while the cabs still on the frame well good luck cutting and removing all the rivets from the old cross member and fitting the V8 cross member in . I did mine on the bare frame . It all depends on what your trying to have when it's done . and how much you plan on dumping into the truck .

[Grumpy old man]

Muncie's and 4 speed Hurst floor shifters aren't cheap . about $2,500.00 should cover it .

[reeltales]

I found a guy who rebuilds and sells the M20 for $750. He has been doing it for 20+ years. The truck is currently stripped down to the frame so grinding the rivets would not be too hard. I currently have the SBC engine stands but do not have the SBC Engine Cross member, or the longer driveshaft, Fan Shroud etc.

The truck is just going to be used by my wife to enjoy and drive some (but not a daily driver). This is why I was leaning toward using the I6 mounts because of the reduction of cost. The problem I have now is the I6 clutch disc was 10" which I think might be too small for the 327 that I have built.

[Steeveedee]

Originally Posted by Grumpy old man

Muncie's and 4 speed Hurst floor shifters aren't cheap . about $2,500.00 should cover it .

I sold my '64 Impala convertible with its SHP 327, close-ratio Muncie and 3.91 posi for $2000 in '82 because my wife didn't want to have to drive a manual transmission car. The guy that bought it new did so to race it. It had only a radio, rear seat speaker and a tach as options beyond the speed parts. Manual steering and brakes. I'm having a sad moment, thinking about what that would bring now.

[Mike C]

From a performance standpoint, the motor mounted in the 6 cylinder position should have a pretty significant effect on weight distribution with it mounted much further to the rear and lower. It also allows for EASY routing of the 2 1/2” performance straight dump repo Corvette exhaust manifold piping. Both of which I would choose for a street truck.