1971 F250 Camper Special with 429 swap and no power

[multiphonic]

Hi all,
I have had my Camper Special for a few years now and have been struggling with it making enough power to go freeway speeds over the pass with a camper on the back. Is this normal?
I bought it with the 429 already in it (previous owner said it was from an early 70's Thunderbird) and after a new Edelbrock carb, new fuel, oil, water pump, timing chain and HEI distributor it seems to run great. compression test shows around 90 for each cylinder and cruising up to around 45 or 50 it runs like a dream. Going up steep mountain passes it turns completely gutless and heat goes way up (water temp around 270) and can only do about 35. Also when I push it on the flats, anything 60 and above it makes the belts squeal. No matter what belt or how tight or loose I make them, they squeal. Tried multiple brands and it makes no difference.
Seems strange for such a big engine but I don't know what normal is.
Any advice or experience? Should I not expect much more with a fully loaded camper on the back?
Thanks.

[Ranchero50]

90 psi ???

I'd pull it apart and find out what you have and build it to what you need. Sounds like cam timing is off or it has really low compression. Not a happy engine.

[multiphonic]

Yes 90 psi... From what I was reading, that isn't too bad as long as all the cylinders are the same-ish. What is normal compression for these engines?

[tnlprt]

I would verify the ignition timing

I would also swap out the timing chain and gears for a set for a 1968 to insure it does not have the late model set which retards the cam

[Beardlife]

90 seems low to me too. Think about barometric pressure wherever you are, and multiply that by your compression ratio. I'm close to sea level (14.7) and my 71 360 makes 120-125 psi (about 8.5 to 1). You might also check your ignition total advance, as I recall a retarded spark will run hotter. Under load like you're describing, you should be losing some vacuum advance.

[bluef250]

i would expect compression at 120 - 140 psi

The cam's in the late 1960's were the weak link in the 429 - 460 engines. So you might start trouble shooting with the cam.