Pontiac Owners Club UK

Has anyone here upgraded heads/cams/lifters/valves on a stick 400 engine? What setup are people running? Was looking to mod. Got hydraulic disc brakes all round so no vacuum issues.

There are several heads which can be fitted to these engines which increase compression and air flow with ported and polished runners and big valves. Edelbrock and Kauffman to name 2.

However it's not usually recommended to retrofit higher compression heads on an engine which is original and not rebuilt ( higher compression puts extra strain on worn bearings and other components etc leading to early/rapid failure resulting in full rebuild anyway)

a lot of mods can be done to increase the torque and power of the engine without opening it up. Headers, exhausts, carb rejet,l and an opened shaker scoop can add upto 30 more horses and similar torque increase.

I notice you have a 403 listed as engine size so is this an Oldsmobile engine? Or are you planning to fit s Pontiac 400 motor?

Theres not as many off the shelf bits readily available for the olds engine and it has limitations in terms of what you can do due to block design etc.

You say it has hydraulic discs all round - do you mean somebody removed the brake booster then?

Forgot to mention that if the engines still "emissioned/smogged up" removing all of that can release another 10 or more horses as well.

Ian, thanks for the top tips, and pointing out my error! It is infact a 400ci. Mine has most of the mods you have mentioned already. It still has the brake booster but I was looking to fit the wilwood delete kit.
I think the only sensible way to go is a full rebuild then! Maybe the Eagle 461ci stroker kit?

A good stroker motor would be the best power and torque upgrade you can do for the money. If your doing that you could go with the edelbrock heads as well. Expect to be around 500 hp by the time you've upgraded the cam, lifters, rockers, heads and done all the machining to fit the stroker kit. All in all i estimate an £8k build budget for that!

Would you be building yourself?

Any machining I'd ship out, but all remove /strip /build and install I'd do myself