[GTOKIDRH]

Does anyone know if HO manifolds will work on a full size car? '67 in particular. I want to wake up the 400 2 BBL in my '67 Executive Safari. Going to swap the cam,change the intake and carb to a 4 BBL. It's a low compression 400 in a big heavy car with a 2.41 rear gear. I realize this isn't a good combination for performance. I'm definitely not looking to make a race car out of it lol. I just want to wring some of that good ol' Pontiac Excitement out of it without breaking the bank. I have a set of high compression 670 heads and HO manifolds I plan on using. I estimate that using these heads should bump the CR into the 9 range. At first glance it seems like the HO manifolds should work. I'm just curious if anyone has ever done it or seen it done before?

[Goatracer1]

You would get a much bigger boost in performance by changing the rear gear ratio. By going to more cam and bigger heads you are going to gain top end at the expense of bottom end performance. A 3.08 or 3.23 rear ratio would work better.