im currently working on rebuilding a 390. im gonna throw it in my tow rig, 75 f250 4x4. it will spend the majority of its life pulling around 7500 lbs. for wheeling trips

what i DO know.
factory 4V (m code?)
its got stock fomoco low compression 410 pistons
standard 390 3U crank
standard 352 D3TE block.
standard C8EAH heads
im not sure what cast # the intake is, but i ASSume standard 4bbl. i'll get the numbers later.


based on the OE pistons, im pretty sure its a virgin block. in fact there still some cross hatch marks showing.

i plan on throwing in some 9.1-9.5 pistons. stock compression is like 8.6 that should help the power output a bit
i MIGHT just buy a crank kit. depending on the condition of mine. i can get a complete kit with the crank for less than $200. i would LOVE to get a 428 crank to toss in there, and build a 410 stroker. but i dont think my budget(what budget) will allow it
i'll reuse the 4bbl thats on my 390. its the OE 650 or 800(whatever came stock) 4bbl.
i'll either have these heads freshened up, or buy a fresh set. at the very least i have to add hardened valve seats to these. and MAYBE throw in the CJ valves to open it up a bit

im not looking to build a major powerhouse. just a good dependable engine, with enough power to motiviate my heavy truck/trailer combo down the road but more power cant hurt

i dont have any pics...but even if i did, theyd be boring. i'll take some of the nice shiny new parts going together.

i expect 1 of the first repsonses to say something about headers...
id really rather NOT use them. i had a set, and gave them away. the truck does have true dual exhaust tho. but...for NOW i plan on staying with the OE manifolds.

where might i find a good 428 crank for a decent price?
basically i need help with what cam to run.
and what pistons i need.

im open to any suggestions on how to build this.

thanks
nevada

 

www.ScatCrankshafts.com this is where i ordered a new 3.98 stroke crank which is the 428 crank, i also have a 292duration cam but this isn't for low end torque so if i were you i would look into an rv cam for really good torque, and we are also running Keith Black performance pistons

 

Any particular reason for not wanting the headers? The FE is notorious for having poor exhaust. Anything you gain in flow is useless unless you can get rid of it. If you do get the 3.98 crank use the 360 flat top pistons and they will put you in the CR you want, plus they're cheap.
This is might be a good cam for you:
Lunati Voodoo
Adv. 262/268
@.050 219/227
lift .540/.552
Lsa108
1300-5500 rpm
I assume you wont be getting above 5500rpm in your tow truck so if you dont mind lugging that boat anchor iron intake around, there's really not a big need for an aluminum. Until your back goes out. Used 428 cranks are hard to come by in the yards. Try craigslist. For what you are doing the 390 will be plenty capable.
For less than the price of a valve job i got some fresh heads with the CJ valves already done, do a little hand porting and they are pretty lively. Look around before you decide to pay someone $1200, mine were $550. Hope it helps.

 

thanks guys.

as far as the headers go..maybe it was just the set i had, that came on the truck. BUT you had to pull the header to get the starter out. what a PITA. it was a two piece slip together contraption.

that, and im on a VERY limited budget. not sure i can afford GOOD headers. the engine has good power now. im not looking for a hotrod. more wont hurt, but i dont need to eek every last bit out.

 

i havent talked to the shop about the work yet. but what does it generally run to have a set of heads done?

i was checking these....and the valves are at different depths....
so the seats are pulled into the head or wtfever happens

 

Sounds like the block is in pretty good shape- is there any ridge, or signs of heavy wear at the tops of the cylinders? If it's not worn much with very little taper, there's no reason you couldn't run it at standard again, and with no ridge at the top, it would probably take a hone, and you could just swap the crank- you already have 410 pistons. If it was worn at the top, with a ridge, the rings would hammer against the ridge area since the pistons are moved up in the hole. If you go the route of the pickup 390 (410) pistons as a 390, you could run a fairly short duration, medium lift cam with a straight up timing set, and pump up the dynamic compression a little. If you're going to mainly tow with it, this would be a good alternative, would really wake it up, but not get into detonation. If you were to go the 410 route, you're going to have quite a bit of static compression already, and could go with a longer duration cam.
There was quite a bit of hype about hardened seats for a while, but you really won't see much diference in real life, and it's not cheap. CJ valves will kind of go the wrong direction for a tow rig, where you need torque. Nice tight guides and a good 3-angle valve job would fix you up. If the block's as nice as you say, rings & bearings, cam kit, and valve job, you'd be good- best bang for short bucks.
If it has the original Holley, I believe that's about 390 cfm- but it's a good carb, fine for towing

 

theres no ridge. a SLIGHT bit of carbon. there still hatch marks in the walls. it looks to be in great shape. so leave the stock size valves? sounds good to me.
damn prop taxes are coming up(just realised it) i MIGHT have to just do a stock rebuild, and take care of the heads.

the carb is a 4bbl. the 2bbl is the 390 isnt it? ive got 1 on my other 360.

oh, and for the cam...i could use links, or part numbers. i have NO idea what im looking for, or at as far as the cam goes. thanks again

 

i wouldn't use 9.-9.5 cr for heavy towing., the more important figure is dynamic compression which takes into account the cam and rods. I also like the lunati voodoo cams but i wouldn't go 219/227.050 duration. I think 200-210 is more ideal, like the old crane 343901, that 204/216 but has .501/.533 lift.

 

Sounds pretty cherry- do you happen to have a set of mics? For what you want it for, if it's that clean and not worn, you should be able to hone it, the block is already worn "straight" under torque, a little touch with a bottle-scrubber would probably do it. If you don't have experience with proper honing, get some help. Check the pistons carefully for worn grooves and cracks, if the bearings & crank looked nice and measure right, re-bearing, and stay with the shorter duration cam with more lift to pump up the dynamic compression a bit, but not too much, be sure you get a straight-up timing set, not a smog set. If you have any money left, you could go for a better intake and exhaust- the Performer isn't a big performance manifold for 428 and 427's but good for what you want, and they're popping up on craigslist pretty cheap- and you can change it any time, if you find one later. For what you want, towing power and mileage, the Performer RPM/ Police Interceptor/ Streetmaster type intakes would be too big

 

the block is filthy. i'll have it tanked, and checked at the machine shop. i have mic's, but not the right kind, or size.

so....sounds like a a hone job re-ring, and bearings, timing set, and im good to go?


the heads: 1 head looks to have been redone recently. as all the (ex)valves are almost flush. the OTHER one isnt as nice. theyre are all sunk in pretty good.

so what i need to know....a good cam. theres been a few suggestions, but its all greek to me. in reality, i doubt this will hardly ever see over 3500-4k rpms. and that would only be for a short time.

thanks for all the help so far. probably saved me from spending money i didnt need to, or have.

 

Clean inside matters, not outside. One thing, if it goes into a machine shop, they're going to want to bore it, whether it needs it or not- it's what they do LOL. We'll punch 'er thirty, and .... Cut the crank, needs it or not.... That's why it's nice to check it out first yourself if you can. I really hate to bore a block that doesn't really need it, the walls just get weaker, and that's less times it can be rebuilt in the future. Most shops will just start checking off every box on the work order, line hone, deck, like a race engine. Most production FE's don't need a line hone at rebuild- and there's ways to check- but Chebbies are another story. BTW, if the shop you're going to is a Chebby-happy shop, that's, umm, not good for your FE. Many things you can check yourself, and aren't really necessary for what you're doing, if it's in good shape now. Of my 8 427's, 5 are straight and runable at std.- and most have been run at std several times- including a '63, a '64, a '65, and a pair of '68 side oilers. The other 3 were already bored when I got them LOL
Sounds like your heads have suffered multiple valve jobs- if the guides are still tight, you could probably put in some new seals and run them. If they're that far gone, rebuilding them could get more expensive than they're worth.

 

Yeah you're probly right that Lunati is a little much. Especially if you are looking at a 3500rpm max. The Crane is a very good cam choice here. I dont see anything wrong with 9:1 though. You get some gain in efficiency(mpg,perf.) w/o risking detonation. Never seen a 9:1 have pinging problems.

Oh and beware the Chebby freindly shop indeed. They treat everything like a 350. All they're analogies are 350 ones. Not good. Ask them something about Fe's, anything whether you really know that much more about the subject or not. They're response should be more knowledgeable than yours.

You can get a set of headers that last a few years for like 160 buck

 

well the outside is covered in grease, and grime. it will be nice to work with clean parts.
the INSIDE is fairly clean. but inside the water jackets is very bad.

i'll be using a shop that we deal with for our shop. they wont do anything i dont want done. the head machinist has built his fair share of 390's. and in fact gave me a part a couple weeks ago, when mine was broke. the little splash guard or whatever..thats under the rocker arms. mine was broke, and crumbling. he had one on the shelf.

heads: i do have another 360 i could pull the heads off of..if mine are too far gone. after he checks everything so i KNOW what i have.

 

what are the casting #'s on those heads?

 

its in the 1st post.

or are u asking about something else?