8k rpm ...

65-440 said

Ok, don't beat me up on this one. No I don't race, I know it's completely impractical .... thinking of rebuilding the engine in my 70 340 swinger in the near future. Will be putting the #'s matching engine in the corner of the garage, I have a complete stock bore 71 340 that I'd build. My problem, I want 8k rpm. Want to build a fun, high revving engine for around town pleasure. Not sure why 8k stands out to me but it just does . My question is, how attainable is this and how much work are we talking about so I don't worry about sending shrapnel outside the engine block everytime I get on it ?

Click to expand...

8k is a lofty goal. Be prepared to spend some $$ developing it. As in build it test it-only to find that combo A didn't work. Build combo B and test it only to find that didn't work either, onto Combo C etc....

Most posters here seem to think a 5500 rpm stroker is the hot ticket. My advice would be to seek out a different forum for this kind of advice--think ST here.

Valve train aside for a moment , take a look at the piston speed.

I've attached a file that shows it will take a 3.31 crank until 8500 rpm to match the piston speed of a 4" stroke @ 7000 rpm. I like to use Eagle Specialty's calculators, they are a lot of fun and easy. So to summarize a 340's piston will reach a piston speed of 122.8 FPS (feet/sec) @ 8500 rpm vs a 408's piston speed of 122.2 FPS @ 7000 rpm. Good luck, J.Rob