8k rpm ...

O.K. My 340 I built in 1977 and on a major budget just out of high school. I had been collecting 340 parts and had a lot of low mileage parts. I had a perfect std bore 69 block, a perfect crank, and with the help of a friend that was a engineer at Chrysler and a racer I put together a nice 340. It had full groove clevite micro babbit mains, micro babbit rod bearings, stock crank, my buddy did the rods opened up the big end so it would have .0035 clearance then cut .001 off the caps, we had .0025 top to bottom on the rod and .0035 on the sides. Now you can just buy bearings with more side clearance but not back then. 10.5 :1 pistons std bore, 400 grit finish, moly rings .040 + 5 file fit Chevy rings, 1/3 the price of mopar rings. X heads pocket ported with a full radius seats, my buddy made his own stones on a fixture he made at Chrysler. Stock 2.02 1.60 valves, dual valve springs, MP cam .572 .296 mechanical with crane ductile rockers, Hooker 1 7/8 super comp headers, MP mechanical 6 pack carbs. Ran 11.84 114.9 MPH in a 64 Barracuda shifting at 7600 RPM
727 Turbo Action VB, 4200 stall TA converter, 5:13 Dana 60 w/spool

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I can say the tach was probably off by 150-200 RPM low (they always are...sent my Autometer dual range tach because it was acting wonky and it was off by 350 RPM at 7500 which meant it was really 7150 RPM) and there is a mile of difference between 7500 and 8000 RPM.

And there is a big difference just getting enough spring to make 8000 RPM. It another deal to make power up there.


Edit: forgot to mention the Autogage tach I replaced with the dual range tach was off by about 125 RPM at 1000 RPM. I could check that with my ignition box.

Most tachs are off.