So I picked up a 1985 5.0 HO Engine out of a mustang with a Performance Intake, 1.6 Roller Rockers, 750cfm Holley Double pumper carb and a e303 cam with slightly ported heads.

I was looking to put it in my 1978 ford f100 shortbed in place of the 300. I am looking to make this truck faster, I do not haul a lot of weight. It has a wooden bed on it and weighs in at around 4K Lbs on the scales.

The engine came out of a 3000LBs car, but since it has some work done to it, would it make my truck a lot faster than what it is? As of now I can barely pass anyone on the highway if I try. I want to make a fun truck to pick on some hondas and the engine only ran me $180.

Also I know the trans will bolt up with my 4 speed with granny, but what about motor mounts? I have heard that the older trucks had locations to bolt the engine right it. Is that true?

 

I believe the engine towers for the 300 and 302 are the same.

 

Yes that 302 will be faster unless your 300 is built up very well. My stock 302 4spd is quicker than a stock 300. The 300 is a low HP low rpm engine in stock form thus its no speed demon. The 300 does offer a lot of torque down low. For the highway driving I did the 302 was a better choice over the 300.

 

What would you guess the power output of this 302 would be roughly? The guy I bought it from said 350hp but I find that hard to believe. My guess would be around 280-300hp.

I just dont want to go through with the swao just to have a slightly less slow vehicle....

 

The engine towers are not the same between the V8 302 and the I6 300.

 

Yeah that's a better guess, and I'd suggest you ditch that monster carb to something more appropriate... like a 500-600cfm vacuum secondary.

 

yes it will b alot faster,the frame mounts from the 6 to the 8 are different,but im leanin more towards 270 280 hp these motors are only around 220 hp stock,the only down fall to the granny 4spd is it gonna tach out pretty quick in 1st n 2nd but in 3rd n 4th is the same as the 3spd n u cant spd shift them but go for it would like to c some pics when u get it that good luck man

 

x2 on the carb. 500 would be best, based on my limited experience.

as for the HP ... the e303 cam is not a very big cam, and should work fine in a truck, esp if the gears are low.... I'd say 290hp on the high side. IIRC the 85 mustang was 260 stock, with a little head work, 20hp from an intake and cam is pretty realistic, maybe another 10 from the heads. unless he really knew what he was doing. GT40 heads and an X303 cam gets you about 340 ...

it will be fun, and better than your 300 ... but I still wouldn't race any hondas ..... just sayin ... it's a truck, let's be realistic about it

 

for carb look for a 600cfm to 650cfm. 500 is too small

 

you know what they say about opinions ... but here's mine

I built an engine very similar to the OP's and used a 600 edelbrock. Until i leaned it out (a bunch) it was a gas hog and a dog. (like 9mpg until I tweaked on it and got it up to 13mpg)

a 500 cfm carb will feed a 302 up to about 6500rpm and will meeter better with less adjustments.

if i could have done it over again, i would have used a 500cfm.

the 600 worked though ......

 

That's what my mindset was until I thought about it some.

Ford shipped their 1983-1985 302's with 600 CFM carbs, that's about 2 CFM per cubic inch of displacement.

So for a 460 you would say 460 cubic inches X 2cfm = 920 cfm.

Did they ship the 460 with a 920 cfm carb? No, they shipped the 460's in trucks with 600 cfm carbs too...

 

That motor won't work with your existing transmission. All 5.0 H.O. engines 1983 and up use a 50 oz. balance flywheel/converter/flexplate and harmonic balancer. All pre-1983 use a 28 oz. balance.


To figure proper carb cfm the formula is CU.IN. X RPM divided by 3456 X VE%.
VE is volumetric efficiency which for a street engine is 75-85%. So if we figure 80% VE, and 6700 RPM the proper caRb size for a 302 is 467 CFM.


The 1985 5.0 H.O. was rated at 210hp from the factory.

 

So long as he has the matching flywheel and damper for the motor, it shouldnt matter what it is hooked up to, so long as the bolt patterns are the same. The imbalance is attached to the flywheel, and the clutch pressure plate should be a neutral balance.

dont try to use a flywheel from a different motor or different year or you will have problems.

I would think that if he has the origional damper to the new motor, then buys a clutch set for his truck with that motor, then gets a flywheel for a truck the same year as the motor .... it should all work. assuming that motor and tranny combo was ever available.

back in the day we called these "mystery machines"
"well, it's in a 79 mustang, but the motor is out of a71 lincoln and the tranny came from a 77 marquis but I don't think ford ever made a 79 mustang with a 429 and a C6." lol ... aaah those were the days ....

 

Yes it will matter. The crank is balance specific. A machine shop that does balancing may be able to do this.

 

not sure where you are coming from on this one .....

the crank is built for a specific inbalance. in the case here, an early 302 would be built with a 28 oz-in inbalance, and a later one with a 50 oz-in imbalance.

so long as he gets a flywheel/flexplate and damper with the right inbalance you could hook it up to any transmission you like. or a water pump or generator if you wish. (ive seen 300 I6's driving water pumps for farm stuff)

torque converters and clutch covers, for fords, are neutral balance. Mopars used to put the inbalance on the converters and clutches, making swaps like this harder.

If I follow what I think you are saying correctly, then a stroker crank built for zero inbalance (most common) could never be used in anything, and this is obviously not the case. so long as you buy a zero inbalance flywheel/flexplate and damper for your zero inbalance stroker crankshaft, you can put it in front of anything you wish.

I went through all of this a few years ago with a crown vic. had a 302 with a 50 oz-in inbalance, and a C4 complete with an earlier 28 oz-in inbalance flexplate, and could not for the life of me find a flexplate that size with a 50 oz-in counterweight. I scrapped the project, but in hindsight, i could have taken that flexplate to a machine shop and had it balanced for a 50 oz-in inbalance and the swap would have worked.

just not sure what you are seeing that i may be missing ....