..i have a 1980 f350 4x4 with a 400 and an auto trans. in it , and am thinking about putting a 460 in. i also have a 6k pound ,27' travel trailer i need to boss around. my carb. was/still is? over fueling..i dont know yet. what i do know is that i was pulling a 6k load today and it was floored and only doing 1 or 2 mph up a moderate grade and half way up i had to put it in 4 lo , just to keep the thing moving .../ on asfault/...this disturbs me deeply..the oil temp went from 185 to 280 in 10-15 minutes...thinned oil from over fueling....no compression....trans....radiator..all the above? im gonna change the oil tomorrow and see if its water or not. the engine sounds fine, no knocks or anything..it seemed ok at 1100 feet , and now at 5300 feet its a whole other cat...i think a 1980' would compensate for that..?..is it worth putting in a new 400 long block ....or just get a 460?..aside from motor mounts and a new exhaust system.../its a single now/..what else is obvious...i plan on putting an edelbrock carb. 600-750 cfm? and a "performer" intake on it anyway..i also plan on pulling 6k loads in arizona's summer /110+/... could it be the trans. , is it cashed as well?...any advice?...thanks..

 

I would do a compression check and see how healthy the engine is. Of course you would know if it uses any oil and how much. It would be a shame to put a whole other engine in, only to find out it was a distributor/carb/vacuum line problem causing the engine not to run well.

 

..well i have 120 lbs. in each cyl. #2 is 75 lbs. is seems. the ford dealer said they should be around 150 lbs. my manual says they should all be within 80%.....so i assume it's right on the line.....maybe i'll just go get a long block 400....?

 

I've got a 400 in a 78 F150 4x4 w/4sd and a 400 in a 79 bronco 4x4 w/auto. As long as the motors are running fine I think they make great motors. The down side I've learned with them They are costly to fix and not much in aftermarket for them. Right now in my Bronco the 400 is running on 7cycl. Last i checked which was a few months ago I put that motor thru living h*** Since I use it mostly to offroad in. I've got a 460 built and ready to drop in it when I find the 1ton drivetrain to handle The power and the TSL boggers I run under it. If I was you I'd go for the 460 since You've already got the 1ton drivetrain under you're truck, Since You'll need mounts It'll cost you a bit more to add the 460 unless ya can locate the mounts in a wrecking yard for a 80+ truck. I bought my 460 from a wreck yard to rebuilt and I got it from a 85 1ton So I got the mounts to Since I was building the motor to drop in my 86 F150 stepside. Once I got the bugs worked out of the EFI system on that truck I stayed with the 302 and soon to have a 351 swapped in it.

I added the edl RPM package to my 460 which gives it great low end grunt for a towing truck, even know my F150 was being built for like a red light to red light runner I went for the low end power and Which I'm glad I did now I got my bronce which will make power where it needs it most.

I'd say look over the pros/cons of boith motors, Prices and Add on's you'd like to do now or down the road. You'll know you picked the right motor to suit you're needs.

 

Well, those numbers aren't very good are they. All I can say is a 400 would be a drop in, while a 460 would require a little bit of parts chasing to get it in.

 

It sounds as though you may have slammed the tranny,( ie., motor runs fine but no power to pull.) Excessive quick heat buildup could be caused from the same. Check your tranny fluid to see if it's up to specs, full and clean.

 

That # 2 cylinder is waaaaaaay to low. Within 80% isn`t correct. The compression in the cylinders should be within 20 lbs of each other, or else head work, or rings. Squirt some oil into the cylinder. If the compression increases, the rings are bad. If the compression stays the same, it`s the valves. You will get way more power out of the 460 engine. JOHN R.

 

A good place to find advice on the 400 would be in the cleveland forum. I can't remember who it is but there is a guy in there that runs or used to run a 800hp 400. They should be able to help you out. Anyway like posted above give the tranny a good check up to make sure its in tip top shape.