Rearend swap or 700R4?

[Arizona64]

I have a 64 Chevy C10 SWB pickup that originally had a 6 inline engine and three speed on the column tranny. I dropped in a 305 5.0L V8 from an old Malibu, along with the 350 TH tranny. Top end sucks, as I can only do about 60 on the highway. I've heard different stories from people, and don't know which way to go. I've heard that a 700R4 would solve my problems because it has an overdrive. I've also heard that a 70's rearend would bolt right on to the frame.
What are the pro's and con's to both options? If I did get the 700, would I need a new crossmember? If I swapped the rear, what do I swap it with in order to achieve freeway speeds? Dval, I know you're probably reading this. What do you think?


Regards,
Arizona64}>

 

[dvalentine]

Hi Arizona.

Our trucks sound like they were seperated at birth !

If you already have the th350 in there then look to make adjustments in the differential. You most likely have 3: 70 gears in there.

With the TH350 at a minimum go to 3: 30 ish gear ratio or 3: 08.
Off the line performance and towing will be better at 3: 30. Top end and MPG will be better with the 3: 08's. Your choice all depends on how you drive.

I suspect that EVEN if you switched to a 700 R4 you would still be looking at changing the rear ratio.

Dval

 

[Arizona64]

Hey, no kidding! What kind of highway speeds could I get with 3: 30 gear ratio as opposed to 3: 08's? Is there any way to go posi also?
Do you have any pictures of your truck? I'm gonna scan some of mine and post them on my website for you to see. You can e-mail me at:

[email protected]

anytime.

Thanks...


Regards,
Arizona64:7

 

[dvalentine]

Normal highway speeds between 70-85 are reachable with 308's.
Same with the 330's. It's just that you will no longer be able to actually watch the gas gauge go down at those speeds anymore.

http://pages.zdnet.com/64moneypit/60to66chevytrucks/id56.html

This is what my panel looked like about a year ago. Made a few changes since then, chrome grill, and deluxe heater now installed.
Been shopping for a body shop to finish some minor body work and get in in final paint. Hopefully, paint will be finished in time for the spring cruising season.

Dvalentine