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Does10's has already done this swap, and he chose to modify the SBF chain by removing one link and using a master link to put it back together. Originally, I tried the same path, but had a real problem trying to find a link to match the Dido brand chain that came in my Summit brand kit.
After about three days and a bazillion phone calls however, I found a source for the right chain that actually came as a complete piece. Turns out that a 69-78 Toyota Corrolla w/ a certain engine uses this chain. The source told me to just go to autozone, and ask the guy at the counter for a
Melling 3Dr56 double roller chain.
Or he could just sell me one for 15 bucks.
I chose "B".
Additional modifications are required to the crank, and the crank gear after that.
The SBF gear has a shoulder that is about .300. This shoulder makes the gear stand way off installed conventionally for that reason. Does10s just flipped the gear backwards. I chose to mill off the shoulder.
Either way, whether you flip the gear does10s style, or machine it off like I did, The crank still has t be turned an additional .050 to allow the gear to sit far enough back to line up properly.
It fits like stock after you go through all of the above. The chain is perfect, just loose enough to allow you to install it.
Now, about the crank gear. I'm also using a SBF harmonic balancer. Conveniently enough, it's about .300 longer than the 250 balancer, so machining the .300 off of the crank gear would've had to happen one way or the other in order for the balancer to fit anyway.
One last "required" modification is the keyway on the crank. It's way too short and does not extend rearward enough to safely secure the gear given that you have to move it back even further. I had my machinist extend the keyway the full length of the crank snout to be safe.