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putting a 4.5" stroked crank in a 9.8"deck BBC?
Posted: Mon Jul 27, 2020 9:48 am
by pdq67
I suppose that some people have done this so just how does an engine run?
Say, a 4.60" bore one.
Looking for stealth max BBC standard deck height engine size is all. I think it will be a 598" engine?
Oh, what length rod do you use?
pdq67
Re: putting a 4.5" stroked crank in a 9.8"deck BBC?
Posted: Mon Jul 27, 2020 10:48 am
by Walter R. Malik
pdq67 wrote: ↑Mon Jul 27, 2020 9:48 am
I suppose that some people have done this so just how does an engine run?
Say, a 4.60" bore one.
Looking for stealth max BBC standard deck height engine size is all. I think it will be a 598" engine?
Oh, what length rod do you use?
pdq67
I have done this but, it is about the limit and needs to be only NA as the top and 2nd ring lands get pretty thin.
4.500" stroke - 6.535" rod - 1.010" Compression height piston.
Re: putting a 4.5" stroked crank in a 9.8"deck BBC?
Posted: Mon Jul 27, 2020 10:54 am
by pdq67
Thanks Walter for posting back.
I think JE will make the needed pistons to make this combination.
I do figure flat-tops to hold the CR down, but I would need to calculate it to be sure what the deck should be?
pdq67
Re: putting a 4.5" stroked crank in a 9.8"deck BBC?
Posted: Thu Jul 30, 2020 8:13 pm
by doncasanova
PDQ - Maybe consider something like this combo:
World merlin 9.850 deck block (#091107)
4.5" crank (center counterweighted)
6.480" rods (Molnar, K1) etc
632 pistons (1.120) comp. height
All shelf parts, & the rod ratio is a tad better than a typical 632.
My 582 std-deck went together no problem using a Brodix iron 4.600 block, Callies compstar 4.375 crank, Molnar 6.480 rods, & CP 632 pistons.
The pistons (#BBC5321-100) came with 1/16- 1/16- 3/16 rings and .180 wrist pins.
Shop used no heavy-metal to balance, & counterweights only needed a few holes drilled.
Got it in my 69 Camaro with a stick & it's a blast.
Hope this helps.........DC
Re: putting a 4.5" stroked crank in a 9.8"deck BBC?
Posted: Thu Jul 30, 2020 9:12 pm
by pdq67
^^^^^^^^^^^
Thanks DC for the build spec's.
pdq67