Building my 360/390 for towing

[1971ford]

I guess they are for sure getting replaced then

[1971ford]

So i have my streetmaster intake on craigslist, and i have someone interested in it ($120)
I asked what parts he might have to trade and he has a set of stock 390 heads that are ported, so i passed on that. But he also has a set of "390 headers for a 1970 ford truck". I'm presuming they are the basic Hedmans
It was a little unclear earlier in the thread on whether or not headers would rob some of my power. Should i trade the intake for the headers (plus him paying something like $75)? Or should i go for stock exhaust manifolds.

[fomocoguy]

Well if those heads are ported on the exhaust side then that's not necessarily a bad thing. If they are rebuilt and ready to go it would save you a lot of cash on head work, especially if they are later model and already have hardened valve seats.

As for the headers, I'm on the fence with that one. I'll let someone else chime in.

[1971ford]

Here is what he said about the heads, It is a little unclear.
"the heads came on a 390 block that i bought from picknpull. someone had gone through the motor at one time. they changed the springs Ect. (porting) the roof of the intake port has been raised, and bowl work on the intake and exhaust sides. the seats only need to be hardened on the ex side, and i don't know."
First time I read it i thought he was saying that only the intake side had been ported, like the EDC ones i have. And im not sure what he means by the seats only need to be hardened on the ex (exhaust?) side.
I'll ask him for some pictures too

[fomocoguy]

Ok, so these heads will need seats, which means they will also need valves ground on at least the exhaust side. I would pass since you're going to have to spend money on them. You may as well spend the money from selling the intake on the heads you've got. If I were you I may try selling the intake on ebay; they seem to bring good numbers on there.

[1971ford]

will do. Thanks.

[fomocoguy]

Hey Ryan, I've got a little info for you. I was under a false belief that the stock heads were probably 71-74cc, but I have learned that there is a good chance your heads are 68cc. If that is the case using the factory 360 pistons will bump your cr up to almost 10:1. What are the casting numbers on the stock heads? If they are D2TEAA then this is the case. I think what I'm going to do with mine is use 390 2 barrel car pistons, which will yield a cr of 9.4:1. They have valve reliefs like the 360 pistons but also have a slight dish. Your other option would be 390 truck pistons, which will make it 8.2:1.
Just wanted to get this info to you before you get it together.

[1971ford]

So i have about $700 right now, im getting ready to take it to a machine shop. Ive been looking at kits with all that we have gone over in mind, what do you think...

Kit A with hyper pistons for $460 + $20 for RV-torque cam. However the pistons arn't dished and they are 4v pistons, so i guess i would have to talk to them and see if they can swap them for car pistons.
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 3042wt_939

Kit B with standard pistons for $390. This one doesnt say as much, and i would have to talk to them to see if they could get a hold of 390 car 2v pistons instead of the standard 390 truck pistons as well, and they don't say what type of cam so i am presuming it is nothing special.
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 1445wt_922

I figure without the kit, and with all the previous links we have gone through, it would add up to about $787, without all shipping and tax. So over $800. (I have a word document with every single thing i should need for the rebuild)
With the first kit ($480), and all the things that it is missing that we have gone through, it would be about $607

THose aren't counting the performer intake, holley carb, exhaust manifolds or machine work of course.
SO what do you think, should i save a few bucks and get one of those kits as long as i can swap the pistons?

[hotrodfeguy]

Are you going with the 390 crank? You can use those 360 pistons again(re-ring) and the 360 rods as long as you keep the 360 piston pins with the rod. The 360 had a thicker pin for the same bob weight as a 390. The 390 had a heavier rod,(060 shorter also) and lighter pin to keep bob/bal weights the same. Now I understand 360 piston and rod combo may be a bit high on CR, but you can have the pistons shaved down a bit to get it to the desired CR. Roughly every .010 you take off the piston makes a 1/4 point lower ratio.I went .040 off my pistons to make a 1/2 point gain from stock on my 390 budget build. 390 Crank 360 pistons 360 rods with heavy pins. I would think if you have that low of miles and hone the block you could save alot of money. Speaking of intake have you sold the SM intake? I would raise the asking price on that, its worth more like $150-200 The single plane works well on FE cars. I agree with previous posts, just run a stock 4V intake it will work good for a tow truck. Spend the money on turning the crank though. You dont want a rod knock later, stock oil pump is fine also for towning. Your heads combustion chamber looked like they were running rich I would jet down a bit also, lean is mean. Just a question but what elevation do you run?

[1971ford]

Are you going with the 390 crank? You can use those 360 pistons again(re-ring) and the 360 rods as long as you keep the 360 piston pins with the rod. The 360 had a thicker pin for the same bob weight as a 390. The 390 had a heavier rod,(060 shorter also) and lighter pin to keep bob/bal weights the same. Now I understand 360 piston and rod combo may be a bit high on CR, but you can have the pistons shaved down a bit to get it to the desired CR. Roughly every .010 you take off the piston makes a 1/4 point lower ratio.I went .040 off my pistons to make a 1/2 point gain from stock on my 390 budget build. 390 Crank 360 pistons 360 rods with heavy pins. I would think if you have that low of miles and hone the block you could save alot of money. Speaking of intake have you sold the SM intake? I would raise the asking price on that, its worth more like $150-200 The single plane works well on FE cars. I agree with previous posts, just run a stock 4V intake it will work good for a tow truck. Spend the money on turning the crank though. You dont want a rod knock later, stock oil pump is fine also for towning. Your heads combustion chamber looked like they were running rich I would jet down a bit also, lean is mean. Just a question but what elevation do you run?

I am using a 390 crank, which will be turned if thats what the machinist says to do (probably will). I am also using 390 rods, and i am looking for some 390 car pistons (4 valve reliefs, dished and the right deck height for a 9.4:1 compression ratio). I haven't exactly sold the streetmaster intake quite yet, but Tom at FE specialities is going to buy it for $140 when i go down there to check out Robroy's 390. So i can't really raise the asking price but he is the only one that was interested in the intake on craigslist. I'm thinking the block is going to have to be bored out again to .030 due to the surface rust, which is going to set me back more because i can't re-use my pistons (the exact pistons i need).
My town is 218 feet above see level (had to google it ) but the races are from 3900 to 4400, not counting mountains in between my house to races.
Thanks for the tips.

[hotrodfeguy]

Sounds like you are on the right track. Just make sure you match the right pins with those 390 rods. Don't use the 360 piston pins unless you are getting it balanced.

[1971ford]

soo I just bought a '74 360 that runs perfectly as far as i can tell.
I am putting it in while i build this 390, so i am not rushing it and so i can drive the truck while it is being built.
My new 360 has hardened seats... right? So should i use these heads and not worry about gettting hardened seats? Or are these heads going to have a different CC?

[hotrodfeguy]

Well the D2TE heads had induction hardend seats first time you machine them, they are just like any other head. I would go for the D2 heads if I was to pick a head. They have the updated intake ports VS the EDC and early heads. Thats what you saw on the head VS the EDC was the lower intake port floor.

[1971ford]

So for those that don't know already i bought a 360 and i am putting it in within a few days, just for a temporary deal while i build the 390. But i need exhaust for the 360 so i am going to do the exhaust that i will want with the 390 so i don't have to re-do it when the 390 goes in and i can drop the 390 right in.

What should i do for exhaust? What size tubing? What muffler(s)? I'm thinking I don't really want flowmasters becuase of the bad rep they have for restriction, what do you suggest. Dual or single exhaust? I'm running manifolds.

[Caseys71]

That 360 should hold you out until the 390's ready. As for the exhaust I'd say duals 2.5" pipe will give you a wide variety of mufflers as that is a very common size. As for the mufflers that will definitely be a hard decision for you to make . There are lots of mufflers out there, I'd say maybe some Magnaflows since you don't wanna run the flowmasters, that or some Dynomax's, I'd just ask around and see who prefers what and why to chose them.