Hello,
I'm needing to know if a 235 & 261 harmonic balancer's are the same? If so, I'm looking for a dual pulley from a 235.

Long story, I have a '57 Bel Air that had a 235 in it. The engine let go and I pulled it to send to a "recommended shop". They told me the engine grenaded and needed to be replaced. Turns out they closed their doors while having my engine. I found a 261, but need a dual pulley for my current setup. Unfortunately, my pulley was on the long block when I sent it in for repairs.

Anyone have a 235/261 balancer with a dual pulley?

Thank you!

Have you tried Davis Speed Equipment?

I didn't know of him. I will, thank you.

The Parts Master shows that the 235 and 261 used the same balancer. The v-belt size went down on the latter series:


GM Parts Wiki P&A - March of '57

Great, thank you!

The most important factors determining damper design are the crankshaft and main bearing data.
The 1954-* 235 and 261 engines use the same crankshaft and main bearing layout.
This is why the Gen-3 292 damper is not as close a match as frequently believed (following that favorite rule "if it fits, it must work"): the stroke length, crankshaft length, rod and main journal sizes, crank throw design, and main bearing layout are all very different.

GM does not spend R&R money to invent new parts unless needed, which is why the SBC engines use many different dampers.