allright here goes, I have a 1947 chevrolet fleetmaster coupe with a 305 small block chevrolet engine, it has the mustang two subframe, turbo 350 ******, 10 bolt chevy rear end all the goodies. The 305 is worn out so........ I have a 402 big block and i need to know if it will go right in place of the 305 or will i need a different firewall. if anyone knows i would greatly appreciate the info. Thank you
I dunno right off hand, lots of variables...how far set back, your front end, where your firewall comes down, exhaust...etc etc... if you got the donor engine sitting there I'd take a tape measure and go to town. there aint no "yes or no" silver bullet answer
Big block chubby is 7/8" longer than small block,, so I doubt it. BUT it is much wider and taller, thats where the problem will be. Edit: that is the block dimensions only,, the total length from bellhousing to water pump will vary according to water pump length. If you are running sbc with long pump, and go to a bbc with short pump you might be okay. For future reference,,, block dimensions for just about everything!!! http://www.carnut.com/specs/engdim.html
Fleetmaster has a 496 big block in his '47 fleetmaster and yes, we had to recess the firewall to make it fit.
Take a look at your steering and see how much room you have from engine to shaft, and how close that sbc is to the firewall for dizzy and right valve cover clearence. I had to redo all of the above when switching from small to big in my 41 chev truck.
I thought it said 37 not 47. Should fit. Six cylynders fit allright and they are longer exept that frigin stock steering right in the way. A bbc without the water pump is 30" long and pretty close to the same wide like 26" I think.
bbc is 5" wider than sbc at the valve covers and a bbc with short w/p is just over 30" long. When building a full tube ch***is drag cars I always set them up for a big block and use a bent motorplate to install a sbc. 7/8"step is all thats needed.
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