2bbl vs 4bbl vs 3904bbl swap

[19674x4]

so im lookin for just a jiffy more power. im debating a 4bbl carb and intake swap. heres my thoughts. i cant get much worse than 8-10 mpg with a 4bbl comapred to a 2bbl that im running now. ORRRR i could swap in a 390 4bbl. i havent had a chance to run it or see what it can do but its in the plans. would i be better off puttin a 4bbl intake and carb on my 352 or just swapping in the 390 4bbl. the 352 is already a pretty strong engine and has good oil pressure.

[DuckRyder]

I think the answer hinges on the exact details of each engine.

[19674x4]

im runnin a stock 352 with a holley 4412 2bbl setup for our stock car. and the 390 4bbl is completely stock and is in 71 f100 2wd

[fomocoguy]

All I can tell you is that I put an Edelbrock intake and 600 cfm 4brl on my 66 F250 with a 352 a while back and it ran MUCH better than with the 2brl. More power everywhere, with major gains over 2500 rpms. At the same time I also installed 2.25" duals with Hooker Aero Chamber mufflers, so that probably helped a bit too. I'm going through the same decision with my truck right now. I just need to get that dang money tree to sprout...

[willowbilly3]

The 352 should be capable of better milage, depending on the weight of your foot. I run a Holley 2bbl on my tired 390 in the crewcab and it does better than that, well maybe not much if I factor in running around town.
I agree that you need to get it breathing better. Headers and good duals are the first thing I would do. You may have to find a 69-later left side engine stand. The earlier ones are different and most header manufacturers don't list their headers to fit the 352 equipped trucks because of that.

[DuckRyder]

If you aren't going to do anything to it, I'd probably go with the 352.

Best plan would be a set of car pistons in the 390 and put it in with a 4 barrel.

[19674x4]

the best mileage iv ever got was 11 and that was on a 300 mile round trip on flat ground. right now im runnin true duals with stock manifolds. my goal is to go with headers but ive already snapped off two bolts so im pretty sure im gonna break em all which mens im gonna have to pull the heads.

[sideoilerfe]

... You may have to find a 69-later left side engine stand. The earlier ones are different and most header manufacturers don't list their headers to fit the 352 equipped trucks because of that.

Not true. I had a 65 with a 352 and installed headers with the stock towers. No modifications required.

[sideoilerfe]

All I can tell you is that I put an Edelbrock intake and 600 cfm 4brl on my 66 F250 with a 352 a while back and it ran MUCH better than with the 2brl. More power everywhere, with major gains over 2500 rpms. At the same time I also installed 2.25" duals with Hooker Aero Chamber mufflers, so that probably helped a bit too...

I think the biggest improvement was the intake and carb. I think people put too much emphasis on dual exhaust and headers. I put headers and 2.25 duals on my 352 and it made NO difference whatsoever. It had 2" duals with manifolds before. However, I have a stock '68 with a stock 360 and it had the stock 2.5" single exhaust with the 2" tail pipe. It didn't like to go above 70 MPH so I cut off the muffler and put a 2.5" muffler and tailpipe on it. It now runs over 80 MPH without a problem. I think putting duals and headers on my stock '68 would be a waste of money. If the engine is built up a lot then I'd say go headers, but if it's stock don't waste your money.

Some people think that a new exhaust system makes the truck faster but in reality, the fact that you now hear the exhaust more makes the driver drive it harder so he can hear it, which in turn makes the vehicle go faster so they just assume it must be the duals and headers.

[1971ford]

none of the above
429. put some power into that 4x4

[19674x4]

gimmw yours and its a done deal

[70shortwide]

none of the above
514, put some power in it
(sorry i cant give it to ya, i want to, just cant)

[rubiranch]

When I first bought my 72 I installed a cast intake and an Autolite 4-V carb and was pleased with the improved power.

The only time I have ever checked the gas mileage has been towing our travel trailer so i have no idea what the mileage was before or after.

[sideoilerfe]

none of the above
429. put some power into that 4x4

I'd take a 390 over a 429 any day. 429 has a 3.59" stroke compared to the 390's 3.78. The 429/460 are good engines and have larger bores but are also 100Lbs heavier than an FE. Besides, They're kind of a pain in a bump 4x4.

[rubiranch]