well the holley carbs are jetted to sea level and are ready to go. which is OK if you want to bolt it on and go, but to start tinkering decrease one jet size per 2000 ft. me thinks. I live in Reno, Nevada. 4000+ ft above sea level so i have to go down 2 jet sizes (from #69 to #67, i went with #64's to give me a leaner cruise in my 600 cfm for my 302) i love carb because thay work with anything. my bros fuelie setup was horrible with megasquirt.

you are correct the offenhauser or any aftermarket intake/exhaust do not come with heat risers or any form of heating to the intake. either plumb the coolant line to the intake, make a heat riser or drive it in warm weather to get alright atomization.

ALSO if you live in a emissions controlled area (dangit) you can't alter the EGR in any way. this prevented me from going to a Weiand intake on my 302 i had lying around, cant ditch emissions!

you can rig it to make it functional, but its not gonna be pretty.

i love the 300 six but it is profiled on smog tests....

 

ok so to sum it up get exhaust manifold off a efi, Y-pipe, and a 390 holly... right now its got a 1bbl on it, any suggestions on a new intake?

also i'm curious about the v8 because i am going to need the power to haul my stuff all over the country. going into air force and going to be moving alot. would love to be able to smoke anything more than a fedex truck. (yes i raced a fedex truck, trust me when i say send AIR MAIL) but mainly need econmy and pulling power. beginning to like the sound of keeping the i6. i have heard from alot of people about how the engine is a tank. proabbly going to do a 4x4 conversion just so i can always be able to get where i need to be... or atleast stand a better chance to. i will be using this to tow a car and probably a trailer. definately a good load of wood every now and then. any more info you guys want just ask. keep the info comming i am looking into the exhaust tommrow. and here's some pics.

 

nice interior, the 8 ball made me chuckle

you should find an offenhauser dp intake, it is one of the only dual plane 4bbl intakes and i have heard very good things about it. other than that you got the cheapest and most effective way of waking this i6 up other than adding headers. the i6 wont beat anybody and i mean NOBODY but a diesel chevette, but is able to tow the mountain effectivley or get great economy(compared to the smallblock v8). and yes, it is a tank thanks to 7 main bearings and a pretty dang good oiling system. run it hard! it will stay intact!

the thing i would go for first is the exhaust since it is a 6-1 manifold (wow...) that is the biggest restriction above 1800 i'd say. pretty dumb idea but i guess it works.

to sum it up
-the i6 will work all day and all night nonstop when the v8 needs a beather or can cool off.(even wonder why they are pump motors or electricity generators?)
-the i6 is a tank of a motor and will outlast any v8 (imho, havent run an i6 or v8 very long past 100,000 miles)
-offenhauser dp intake, 390 holley, efi exhaust, y-pipe and maybe bump the timing up to 10-12* depends what its set at.

 

You have to drive lots of different vehicles, including tractors and other equipment to finally experience what the difference is between torque and horsepower. I will try to explain what I have experienced.

With the 6 you definitely will not win any races. Running empty it will seem it doesn't have any get up and go at all, and you will be disappointed in it. But get it loaded, and you will be surprised to find it's still it's old doggy self. The load makes a difference, but less difference than with a 302. And you will find when you really need the engine, it seems to pick up some sort of grunt down low and will hold it. Even though you are going slow, it seems more willing to pull.

The 302 on the other hand is a very lively, and willing to rev and running empty seems to have a lot of power and get up and go. Do a little work to it, and it's a very fun engine to drive. But when you put a load in or behind the truck, you will find the difference very dramatic. The "power" seems to go away very quickly. You will find yourself using the lower gears a lot, and having to rev the engine very high to keep moving. You start feeling sorry for the engine because you have to run it so hard, but use any higher gears on a hill, and it will bog down. It just doesn't have that "solid" feel the long stroke 6 has when pulling.

 

Think this through. Right now you have a weak little 300 six that is starting to show signs of needing a rebuild. In my mind there is no sense wasting time or money on that engine. That brings us to an engine swap. If you're gonna go through teh trouble of an engine swap why bother with a small engine like a 302 or 351? Just go straight to a 460, it's pretty much a bolt in swap on these trucks.

A 460 is the onyl way to go if you're gonna be pulling a trailer. It's just not fun pulling anything substantial with a small block or six. It's also not fun pulilng trailers with short trucks. My '86 F-250 Supercab pulls much better than my '83 stepside did. That stepside had a 302 and was terrible for pulling trailers of any real weight. Heaviest I pulled with it was about 6000 lbs, give or take, and it was a turd. Ate through gas like mad and took forever to get up to speed. That was with engine work too, intake, cam, carb, long tube headers. My '86 has a 351W and ZF5, and it struggles to pull my 4000 lb boat/trailer. Small blocks are pointless, and don't save much gas. When I converted from mild 302 to mild 460 in my car I lost about 1 MPG and gained a whole crapload of power and acceleration.

If it were my truck this is what I'd do... Build a nice mild 460. Ported D0VE heads 9.5:1 compression, Lunati Voodoo or Comp Extreme cam (I like the lobe profiles on these cams) right about 262-268, Edelbrock RPM intake, Holley 750 VS, long tubes into 3" collectors and side pipes. If you got deep pockets do a 4.5" stroke crank for a 545 and go with more duration on the cam to keep it around 6000 RPM peak.

Note to swap this motor in there you can use all factory parts except you will need an oil filter relocation kit as your crossmember has no accomodations for the oil filter. Mount it on the inner fender or wherever you like.

For a trans I'd do a ZF5 to maintain decent highway MPG. They are great transmissions. I'd do a married NP205 on the back. Build a crossmember for it though, as the 205 case is heavy. I'd twin stick it while you're at it, and probably run a 3.73 or 4.10 gear in the axles. Also a double cardan shaft in the rear would be prudent as your driveshaft angle won't be pretty if you do much lift. The ZF5 is a bit longer than the NP435 and will rebuire moving the trans crossmember rearward. The NP205 isn't exactly tiny either.

If want to do a lift on the truck go with a '78-'79 high pinion Dana 44. It's almost a direct bolt in on the '80-'96 F-150/Bronco except you need the lift for the center section to clear the crossmember. If you don't want to do a lift or don't have deep enough pockets/can't find that axle/whatever then a Dana 44 TTB setup is a direct bolt in. You will break it with the 460 if you don't use discretion offroad. Should be fine for street use, snow, dirt/mud roads, etc. My most common failure point on my old D44 TTB was passenger side slip joints in the axle shaft. I always carried spare shafts when wheelin'.

In any event that's what I'd do with the truck. It's all simple, easy, and mostly a bolt in deal.

 

very nice opinion... but im betting this guy has to pass smog and ya know DRIVE the truck. if he wanted a 460 he coulda bought an f250 or a 350.
the i6 will do fine and save some money. i see no signs on my dads i6 faltering that has over 200,000 miles on it.

you bet the 460 will kill any smallblock, but the fact that he has a smallblock trans, light duty rear end and a mileage miser of a i6 (if properly geared) i see no reason why to swap. go get another truck to tinker with or buy a mustang and drop the 460 in and go drag racing

the i6 is plenty of grunt to tow or putz around town and he'd save money because he has it already, not a motor you gotta machine and build.


P.S. a cummins diesel or an international 7.3 will destroy any 460 in towing and economy, one way or the other. or both.

 

In NJ my truck si subject to the emissions ****'s as well. Doesn't stop me from making it into what I want. The OP just needs to figure out what he wants. If it's a straight six then spending the money to upgrade it to the performance of a mild 302 may be worthwhile. It seems like wasted money when the cost of converting to a 460 is fairly cheap. At the end of the day you still have a small engine not suitable for towing real loads. Another consideration though is a SWB truck is not suitable for towing real loads either.

I also think it's a shame to waste a nice stepside on a 2WD six. Regardless, the OP started the thread saying he wanted to do a V8 swap and mentioned the possibility of converting to 4WD. As for the 8.8 not holding up... They are a decent axle and can be made to take some power. A 9 inch will bolt in and take anything a 460 can throw at it. Also a Sterling 10.25" and Dana 60 will also bolt right in. I was not under the impression that the OP was gonna be using this truck for anything more than mild trail riding or street use, so I wouldn't expect the 8.8 to have much trouble.

A 7.3 conversion would be nice but that conversion is a lot more involved. Not certain the OP would want to get involved with such a swap.

 

"when the cost of converting to a 460 is fairly cheap"
What do you call cheap? A good used 460 is hard to come by and pretty expensive to rebuild when you're talking about a $1500 truck. Maybe I'm just jealous cuz I've got a small block.

 

Ok, honestly cadunkle, I like your idea of a big block, should push a pretty cozy 400 hp and 400 lb ft of torque. (I built on very similar and put it in my 88 F250 supercab backed up with a c6 running planetaries out of an e4od (1st and 2nd gear) It hauls *** no mistake. I can pull an easy 6000 lbs without breaking a sweat. It also packs 3.55 rear gears and a limited slip rear. That drivetrain cost me about 9000 bucks fully rebuilt. I love that truck. Its getting a gear vendor next summer, cause it needs and overdrive. Right now it runs about 23oo rpm at 60 mph, and gets about 16mpg all the time. (Canadian gallons). My "beater" truck is an 81 F100 Explorer. When I bought it it had the 300i6. bone stock, and worn out. It also had the 4 speed manual. I still have the manual, but I swapped the motor out for a 351w. Its ugly as hell, but damn is it fast. I figure its putting about 350 horses 350 lb ft down. And its way lighter than my supercab. I use it for hauling garbage to the dump, driving to work so in the snow and salt cause the body is ugly. The bottom end is stock, pulled it out of a wrecked truck with about 125000k on the odometer, yanked the garbage heads off (69 cc open chamber with thermactor junk in them Yuck!) and replaced them with 1969 351w heads that I scored at a swap meet. they have bigger 1.94 intake valves, I did a really mild port job, polished the exhaust, port mached to a preformance parts no name 4bbl intake and an old set of hooker headers that I had in my other truck, cam is a comp 262xe flat tappet , roller rockers, procomp hei distributor, demon 625 vaccume secondary carb. Bolted it up to the old 4 speed, tweaked the motor mounts to make it all fit, and put a used rad in from an 85 f150 that had a 302. This is a very fun truck to drive, it winds like a 302, but makes reasonable power down low. It starts pulling at about 1500 rpm and hauls to 5000. The best part is it cost me about 2500 bucks. I put steel 8 inch wide rims on all round (came off a bronco) with MT ATZ tires. It will do an easy 100mph, pull a 4000 lb trailer with a little bit of effort and is at least as fast as my buddies hemi powered ram (and he paid alot more for his truck) I trust it to go anywhere. Mileage is around 18mpg WHEN I AM BEING NICE. thats highyway crusing not playing, in town its more like 14.
I have a 1970 f100 sport custom thats my first truck. Its also in about 2000 peices right now. Frame up rebuild. When I bought it it had a 302 and a top loader 3 speed, stock. I added headers and an hei distributor, an big fat tires. It was quick, tons of fun to drive, and great for hauling the dirt bike or quad. I pulled a 400 lb trailer with it once and wont do it again. it got me about 16mpg empty, with the quad in the back 14, I would imagine a rebuilt version could do better but the stroke is just too short for low rpm torque. The 300 i6 is much slower, much better torque and easy to wake up ith aftermarket stuff, but it would cost alot more and never touch my 351. Anywho thats my rant. Good luck.