Have run into this problem a couple time's and thought I would relate my fix for it. Had my "old" Fairbanks converter redone for the 347. Had to have a bit more stall and found out after they opened it up, that my suspicion's were right about it being destroyed and causing the 331 crank to be forced foward and eventually leading to the demise of said engine. Got it back from the expert on rebuilding them, and with the new SFI flexplate I had used to balance the rotating assy, found out the 1/16th block spacer was not allowing it to have enough clearance to pull up to the flexplate. Only about a 1/16th which is not in my realm of being enough and causing another explosion of the newly assembled 347. Was going to try and make a new block plate out of 1/8th steel, which would have taken quite a bit of work and machining. Then I came up with a little simipler fix. Found a piece of quality 1/8th steel plate at the scrap yard, about 12x12 inches. Took some poster board and another bell housing and made a template of the mounting circle, where it bolts to the front pump. Transferred it to the steel plate and with the blue wrench, drill press and die grinder etc, made a spacer to go between the bell and pump. Still had plenty of mounting surface for the bell to sit on and this actually pushed the C4 case back from the flexplate 1/8th inch. Removed the block plate and had perfect converter clearance. Just have to make sure you don't warp the cut out ring spacer during the process. Not all converters will need this modification, mine is a 9inch with a seperate mounting ring on the back. Hope this may help someone in a similiar situation.
Did the starter line up ok? Never thought of "adjusting" clearance this way, would be one way if starter is right on. Good Thinking!
Using a mini starter, have never had a problem, stock one may be another story. Could cut a shim out of the block plate and use it behind the starter if necessary.
Strange. You've got me wondering about mine now. (I'm paranoid) 'Glad you found the problem and the fix.
I had to shim my mini starter. Just bought the ultra bell and have to check my clearance's on everything. Old c-4 bell showing hairline cracks.
For anyone's information, and from my research, the Ultra Bell is the only SFI housing that is narrow enough for 1-3/4" tubed headers. The "other brands" (that can be used for both 157 and 164 flexplates) is too wide because it has to allow the starter to be moved farther outward to accomodate the 164 tooth FP - taking away more of what little space there is even with the small bell-housing. If anyone has a different solution to an SFI approved Bell-housing that provides optimized header clearance, please speak up. Quoting an entertaining politician and billionaire, Ross Perot, "I'm all ears!"
I had to do something similar on my 460/c4 combination. I had a B&M holeshot C6 converter and used a Performance Automatic C6/C4 adapter on the C4 input shaft. It worked fine until I dropped the engine with the trans still half way attached which bent the pilot on the converter. Had a local converter shop build me a C6 converter so I could run the same deal. The new converter has a threaded flange that uses bolts to connect to the flexplate - rather than studs that go through the flexplate. I connected the trans to the engine and noticed that I could not spin the converter like it was bound up. Long story short - New C6 converter measured dead on length of stock C6 converter. Old B&M C6 was about .120 shorter than stock C6 but coincidentally the same length as a stock C4 pan fill converter that I had. Used some flat plate to make a spacer using a engine plate as a template. Stacked the thick spacer behind the stock engine plate so no starter spacing was required because the distance did not change between the flexplate/engine plate/ starter. All the spacing was added behind it. Lesson learned - C4 converters and C6 converters are ALMOST the same length where they can be swapped. Some converter builders use the slightly shorter C4 case length for both. It does make a C6 have slightly shorter amount of engagement on the pump. Is this a problem? Probably not for most street applications. My opinion. Measure twice and cut once. Brand x interchangability thinking will get you in trouble with C6/C4. Cleaver
