Ok this is what I need some help with. I have an 88 F-150 4.9L EFI 2wd. I don't use the truck to do any hauling really I like the way it looks. I want to swap the 300 out with a V8 for a few reasons and this is where I would like advice. I want the snap back acceleration with good power on the high end too. I would like to keep the gas mileage decent also, last time I checked right now on my truck I get about 17mpg. I have free flowing exhaust I believe 2 1/4" pipe going straight out the back through a glass pack, I replaced the fan clutch with an electric fan, and I have some what bypassed the smog pump. I have the 5spd and I'm not sure what the gear ratio in the rear-end is the tag reads S806D - 887L30. I know I want higher gears but I'm not sure what to go with. Now to the motor swap, my teacher is a good friend of mine and has a 289 in a 68 Mustang he will sell me cheap, at a glance at the tranny I believe it will bolt up to mine. I plan to keep the short stroke on it put flat top pistons in it and I want to get a 9:1 compression ratio, I think I should port the intake and exhaust valves but I'm not sure how much and what else to do to the head. I plan to travel with the truck is why I want higher gears in the rear-end but I want to beable to still boil the tires and shoot. What I want to know is should I get the 289 for what I want or should I shoot for a 302 or 351? What gear ratio should I use for good highway rpm and beable to have the off the line acceleration that will pull you back in your seat? What should I do to the motor to get the power I want with good gas mileage? I also plan to balance the entire motor. Any advice would be very much appreciated thank you for your time.

 

Ok on the tag inside the door the tranny code is M and the axel code is 18 which shows non-positraction differention with 3.06 gears in it. That throws off my questions, now I dont want a one wheel wonder when I spin tires either. So do I need to invest in a rear-end from a junk yard or can I replace the gears in my rear-end and get the limited slip. Also what do I do with the gearing in the rear-end to acheive my goal?

 

I think those gears will be just fine for what you want to do. If you want to add a limited slip on a budget, you can add a stock Ford unit to it fairly easily. Look for one from another F150, or Explorer. A while back I saw reconditioned ones on Ebay for about $150. New at Summit they're about $250 I think. Important thing to remember is that you want a diff for 31 spline axles, which is what our trucks have. Mustangs had 28 spline axles stock, so that won't work easily for you.

If you really want to have lower (higher numerically) gears, you could swap an entire rear axle out for something with 3.55 gearing and the limited slip. You could also change the gears in yours, if you know how to set up gears or your teacher is willing to show you how. Important parts of choosing gearing are tire size, your intended use for the truck, and powerband of the engine.

As far as the engine, I have no idea if it'll bolt up to your trans or not. Personally, I'd go for an HO 302 with GT40 heads, long tube headers. I think this would be a better option for fuel mileage, driveability, dependability, etc.

Important things to think about are laws in your state about engine swaps to earlier vintage, and emissions.

 

Thnx I should be fine with the emissions and all here. I'm not positive but I believe the motor could be the start of the 302s in 68 when they increased the stroke and all, I was just reading about that. The reason I was going to get the 289 was because his dad is the original owner, its been taken care of and I can get it for around 200$. 250$ isnt bad for that part for the rear-end and my teacher happens to know the guy in town thats apparantly the best guy for gearing in the area. I plan on running 15" rims, I currently have 255/70/R15 BF Goodrich radial gts on deep dish bullet hole rims but I need to replace one or all of them because one is bent, I would like to get another set of them thats clean and put shorter wider tires on them. Also right now with the 5spd mazda? tranny in it in 5th at 65mph I'm @ 2000rpms. I would like to be @ 70 or 75 @ 2000rpms but still have the *** to spin them and launch. Is that possible or rediculous?

 

Also you dont think the 289 would be as good or close to the gas mileage of a 302? What did you mean by driveability? Thnx for your time.

 

That's not going to happen with a 289 or 302, you need a built 347 or 351 it's as simple as that.

 

You want the longest stroke you can get IMO. The 289 has a 2.8" stroke, 302 has a 3.0" stroke and the 351 is a 3.5"

Shorter stroke motors are good for RPM, but you're going to need gears to get a heavy truck going. If you're at 2k rpms @ 65 you're going to need less gears to get to 2k @ 75. Probably 2.73 gears. That's going the other way if you want to race off the line. A 351 will pull a lot harder then a 289 with those gears.

 

If you're looking for power on the cheap, getting a similar displacement V8 won't do you much good... A 302 is really a 4.9L displacement, same as the 300, they just called it the 5.0L for PR and to differentiate. You're going to trade gas mileage for power and vice versa. If you want to burn tires, you're probably better off going with a stock 351 than a built 302 or 289. You're not going to get something for nothing here, it's always a trade-off when it comes to engines.

 

I think anything carbed won't get as good of mileage as a later model fuel injected engine. Well, not without fine tuning anyway.

Driveability, as in not having to mess with the carb all the time, better throttle feel, etc.

This is one of those cases, that you'll need to compromise one goal or the other to be happy.

And listen to Conanski, he knows his stuff!

 

Thats what I thought, I was hoping that the 289 would have the power to do that because I can get one thats in good shape for like 150-200$. Should I try to find a 351W or a clevland? Being as my truck is already EFI would it be relativly simple to put a 351 EFI in place of the 300? I know that I would have to swap the mounts, will the tranny bolt up? Should I swap the tranny for one with taller gears then maybe change the ratio in the rear-end to like 3.23 or 3.30 gears? Also are the connectors the same for the computer and sensors? I saw somewhere that all I would have to do is get the computer from the truck with the 351 I was getting. I was told one that balancing the motor was relativley simple to do and I want to know what are the benifits of doing that? Since I am going to rebuild the motor should I get the intake and exhaust ports opend if so to what size, also what factors do I need to consider in deciding the cam I put in it. Thank you all for your time in helping me.

 

A 351 will do what you want, but so will a mild-moderate 302 rebuild. I would look into what motor would be easier to put in and go that route.

 

i think the 289 would be slower then the 300. Its really not meant for a heavy truck. So you defiantly need a 300, 302, 351.

If you want power, you might as well go with a 351. It has more potential and will make more power more easily then a 302. Its been said, there is no replacement for displacement, 50cid is alot more power.

the 5 Speed in the truck now wont hold up to a 351, it was never even put behind 351's. It may hold up to a built 302 for a little while. But i wouldn't be surprised if it didn't. So this could be a major issue. You might want to look for a good 351/auto combo. The only way you'll find one for a manual trans is with a 4speed or a 5speed f250(ZF-5)

and with any v8 swap, you will never see 17mpg again. Regardless of what anyone says. you'll be in the 12-14mpg, maybe 15mpg on the highway, if you easy on it.

 

Yeah that makes sense, I didnt think about the tranny issue but thats not that big of a deal. I would like to keep the tranny manual but what good auto trans could I get for it? I was expecting to loose a little gas mileage with the swap also.

 

A C6 is a safe bet. Only auto I'd put in, but that's just because that's all I've ever had, and they've done a lot of ball busting pulling.

But if you're going that route, it'd be easier to throw in a T-18/19.

 

If you have the option, it might be worth driving a couple of trucks that have different rear ends to see what you like. I had a 351 with a 3.55 rear, and that thing would tear off the line, but would run out of air as it wound up. Pick a motor first, then the gear can follow. what works for one engine, might not work as well for another.