My neighbor has a bone stock 68 Cutlass with a 350 2 barrel carb. He has recently just ordered a 4 bl Rochester carb to go with a used stock 4 bl intake manifold. He has yet to install since he needs to hot tank the intake. My thinking is that he will need new linkage and fuel lines. Is this correct? Are there any additional parts he would need? By adding just the intake and 4 bl, what kind of power increase would that net? Thanks for any info you can give me.

 

you/he won't gain a lot from a 2-bbl. to 4-bbl. swap, assuming the carb. is calibrated for the application. in '68, the factory 4-bbl. equipped cars had an advertised 10.25:1 compression ratio vs. the 2-bbls. advertised 9:1 compression ratio. the distributor advance curve is a little different and the 4-bbls. had bigger valves.

the linkage and fuel line(to the carb.) is bent differently. and iirc, the 4-bbl. uses a different fuel pump.


bill

 

I'm afraid I must disagree. Except for the W-31s, all 68 350s (2bbl and 4bbl) came with No. 5 heads using 1.876/1.562 valves. I did exactly this swap on my first car (68 Vista with 350). The Qjet makes a noticeable difference. The fuel line can be rebent. The original throttle cable works. The original fuel pump works fine. The distributor advance can be tweaked. You do need a different air cleaner housing, however.

 

as far as the throttle cable goes-i had to replace the one on my '69 cutlass s when i did the 2bbl. to 4-bbl. conversion. i also needed the 4-bbl. throttle bracket.


bill

 

Bill and Joe, thanks for the replies. I know he was hoping to make the car a little more powerful. He'll be happy to know he should be able to bolt the swap right in without any additional parts. Is a distributor recurve neccessary? Any tuning hints I can pass on to him?

Thanks again.
John