Re: Project Blown 305
 

The 478 has a longer stroke than the other V6's, hence the reason for external balance in this case.

Re: Project Blown 305
 

I see no reason why a gas 478 block couldn't handle lots of boost. Mine will only handle 11 pounds or so and I'm not worried at all. With it, came a Clark VO 285 transmission with a .83 overdrive. My cruise RPM at 60 will a little less than 1900 RPM.

Re: Project Blown 305
 

This thread has been cleaned to bring it back on track. Remember Gentlemen, we have rules in this forum.

Stay on topic. Cutty, good luck with your project.

Re: Project Blown 305
 

It's absolutely impossible to internally balance the 478 crank, I requested the balance shop to see what they could do and the end result was they put as much weight as they could to the crank but still needed a good amount of weight on the flywheel and front pulley. The only internally way to fully internally balance one is to stroke it and increase the bore, the end results would be 523 cubic inches.

Re: Project Blown 305
 

The Clark is a five speed. If the nomenclature only had a letter, it's a non overdrive. An O after the letter indicates overdrive. For the other larger truck transmissions, I'm not sure how they denote it in their nomenclature.

I was lucky as this is the transmission that was behind my 478. My truck is also a 4 X 4, but it has a divorced transfer case so it is only a simple matter of fabricating a shaft between the transmission and transfer case.

Re: Project Blown 305
 

Finding a Clark 280 or 285 overdrive is not going to be easy. I have been searching for one the past 6 or 7 years for my Ford to no avail.

My plan is to just use the large truck adapter plate and flywheel and run an overdrive tranny with an SAE bellhousing pattern. The Spicer/Tremec 6+1 seven speed has been turning my crank of late but any Fuller 5 or 6 speed would work fine.

Re: Project Blown 305
 

I figure if I shed serious weight off the 478 rotating assembly by stroking and aftermarket parts that aren't giant I should be able to internally balance it.


Shoot! there sure are a lot of options, I just need something OD to make it streetable and something that bolts up since my engine combo is gettin more exotic haha.

What would you recommend for an OD equipped trans that's relatively readily available for a reasonable price??

Re: Project Blown 305
 

Are there big truck transmissions available that have a married transfer case and OD?
Would they fit in the run of the mill c20's?

Re: Project Blown 305
 

No, but custom adapters have been made to couple 6 speed fullers to married transfer cases.

http://www.4btswaps.com/forum/showth...-Transfer-Case

Re: Project Blown 305
 

I don't know of any as even the big stuff years ago used divorced transfer cases.

I would find a NP205 divorced style out of a 70's Dodge 4x4 P/U or International light line 4x4. Both had the front drive coming out of the right side if you are using a 60's to late 80's GM front drive axle.

Ford also used the 205 divorced style through about '77 on the F250/350, but it drives on the left, so you'd need a Ford front drive axle.

The 205 is all gear drive and is the strongest of the light truck models. I converted my truck (a 1965 Chevy) after the naturally aspirated 454 chewed up the original Timken T221. It has held up under the turbocharger since 1986.

Are you wanting a manual transmission only or are you also considering an automatic?