I have a 1982 f100 with a 302. I recently rebuilt the motor and got a 4 speed for it. I put a rv cam and aluminum intake with 650 cfm carb on it. Those are the biggest upgrades really. I'm pretty sure the carb is too big for it though. The truck now has no acceleration or power except in 1st gear. I really Boggs down in 4th gear. I'm pretty sure it's because of the big carb. Does anyone have any tips?

 

While 650 CFM is probably a bit more than the engine needs, it isn't causing the problem. That's because the carb only gives that CFM with the secondaries open, and they aren't open until you both give it full throttle and wind the engine way up. In fact, you can't cause the secondaries to open unless the engine wants them - assuming you have a vacuum/velocity-operated carb.

Tell us more about your engine, like the cam and the intake manifold, awa the carb.

 

448/472 valve lift on the rv cam. The intake a dual plane pro comp aluminum intake. I recently put new rod, main, cam bearings. New sealed power pistons with Hastings rings and all new valves. And a bunch of other stuff. It's pretty much a new motor on the inside

 

Oh and I think te carb is a 600 not a 650. Because the numbers on the front say its a 1400 and that's usually a 600 right?

 

Just to make sure I'm understanding:

1. Whose RV cam? I'll look at the spec's and recommended applications.
2. Is this the intake? Pro Comp Intake If so, it says "180° dual plane medium rise design for outstanding power from 1500 to 6500 RPM." That means it isn't going to pull very well until you wind it up - which, by the way, is not what trucks need and may be part of the problem.
3. Did you have the block bored or did you just put in new rings?
4. And, did you have the valve seats ground or just put in new valves?

I just want to make sure we aren't missing anything.

And, if you mean an E'brock 1400 then yes, it is a 600 CFM carb. And it still isn't overkill. Those secondaries won't start to open until the engine is winding up pretty well, and you said that "The truck now has no acceleration or power except in 1st gear. I really Boggs down in 4th gear." I assume your name isn't Boggs but that the engine bogs down in 4th.

And, while I am asking questions, have you changed out the ignition system? That truck probably came with the DS-III ignition and EEC computer. If you didn't change that then that is part of the problem.

Again, we need all the details or we will be chasing our tails. Please describe all that has been done. And, by the way, telling me the lift on the cam is a good example of part of the information. First, I have to assume that those #'s are at .050" lift since you didn't say. Second, there are many different "RV" cams, and some are mild and some aren't. So, please tell us the details. I want to help but you have to help me by telling me what you have. I will not guess as that will just cause more problems than it will solve.

 

Edelbrock? 1403 = 500cfm, 1406 = 600cfm...both with elec choke

 

what gears do you have in the rear end ?

 

I'm not sure about the cam brand I bought it off of eBay lol. And yes that's the intake I have. The blocks not bored. And it has a eBay brand hei distributed

 

I was afraid of that. There's no reason to do any more diagnosis until you do at the very least a compression check, and preferably a leak-down test. I seriously doubt that you have reasonable compression on any cylinder, much less all of them. Without compression, good compression, the engine will never, ever run correctly.

 

And the valves are seated

 

And I got 3.25 gear ratio

 

I got 130 on all cylinders

 

Ah... the perfect circle in an egg-shaped bore?

Yeah, truly rebuilding an engine requires a machine shop and very accurate measurements of all the parts and is best left to the experts who know what they're doing.

Merely replacing parts isn't likely to get you good results.

 

do you have at least 12vdc going to the distributor ?

 

Yeah I had to run 10 gauge wire and a relay