83ttopgt

Does this sounds like a decent combo? I need to buy pistons for the motor anyway, so I will buy them with valve reliefs

I already have the 69 block and I have a set of DOOE heads, also have a z303 cam hanging around (very low miles)

Will be converting the 351 to a roller anyway, with link bars no matter where I end up

I am planning on gasket match/ mild porting job to the heads, with the addition of screw in studs and guide plates.

I am looking into the larger chevy valve thing (a point in the right direction would be ok too.)

Also considering a 393 bottom end with 3.85 crank, 351w rods, and 302 pistons.

May someday upgrade the heads, but I may not. unsure at this time.

what kind of power would the 357 make? and the 393?





Also considering a cleveland head swap, but can only find 4v heads in an open chamber configuration.




I have no money for aftermarket heads right now. I can piecemeal the windsor or cleveland heads as money permits and do alot of the work myself.

69mach1377

The W heads will provide good low end torque is about the best I can say about them.
4V C heads will do the opposite...high end HP. So neither is a good bet depending on what the use is.

67mustang302

Cleve heads will require a bit of work to make them function right, plus a new manifold. I would say use a better cam than a ford alphabet, but since you already have it....

It should run decent, but won't be anything spectacular. You could build a 393 or 408 and just run those heads and the cam for now, it'll be rather wheezy over 5k rpm, but should make a lot of torque. Then just put some AFR 195's on it later with a better cam.

83ttopgt

Just looking to see where I should start. Maybe I will just start gathering bottom end pieces and save up for heads when the rotating assembly is done.

I just dont have the $$ for aluminum heads this year. Might next year, who knows.

barnett468

you can find biger valves in the online manley catalog . . they m list all the specs . . the next suze up os as big as i would go . . the exhaust needs more work than the intake.

the 4v clevo heads thru 72 will be far better for a 393 . . the 73 4v heads have smaller valves . . open chamber ones are what you need there or you will have too much compression.

stock windsor and clevo rods are good to 7000 rpm with good rod bolts.

83ttopgt

Ok so for numbers on a clevor 393:

So some numbers:

3.85 stroke
5.965 rod
1.647 compressed height piston
total 9.537

Deck height 9.48

Shave .040 off the top of pistons (part number L2379f40) which I read some where is perfectly fine to do (or just run .120 head gaskets for same effect)

that should leave the piston flat topped (with valve reliefs) and sticking .017 out of the block.

if I use a head gasket around .085, it should net around 10.004 static compression ratio and around 393 cubic inches which should help "suck up" the low speed problems with the 4v heads.


Cam choice to come later in the build.

If I run a scat 3.85 crank, and those pistons, stock rods with arp hardware how fast can I spin it?

also which is better, my 69 rods or the "truck football" rods as far as rpm goes?

Thanks for all the info guys, I am the kinda guy that has to have everything nailed down before I start anything.

The reason I keep going back to the pistons I chose, is because I read of a couple people milling them with no issues, and they are forged and a decent price. I don't mind spending money, it will just take longer to complete.

Also, assuming custom cam, that motor should be like 450 or so hp, right?

anyone know of a free version of something like desktop dyno I can play with?

Should I start a new thread dedicated to a clevor? I think I have decided thats where my money is going?

barnett468

ok, well some pistons can tolerate .020 off the top and others can't.

you want to spin a 393 past 7k . . why?

you need forged rods and an internally balanced crank and an ATI damper.

also i would run lite weight valves with undercut valve stems and titanium retainers and lash caps might be good.

a 393 with pre 73 4v clevo heads properly done will hit 450 hp, but different dynos give different readings so they are just kind of a guide.

what is the part number on the rods . . if they are dizx-aa they are boss 351
.

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83ttopgt

past 7k was more directed at a 357. I worded it wrong. That post was copied from another forum, so some of it might be out of context.

The 393 will make better use of the clevelands ports, where a 357 will have to spin alot to use it all.

I would like to run internally balanced, probably will

Like I said I read somewhere those particular pistons can take .040, but I might go 20 and run a thick gasket. Opinions on 10/1 compression with those heads?

Heads are december 10, 1971 4v open chambers

barnett468

yes you can run 10:1 with clevo heads if you have the octane for it . . either 91-93 or e85 etc..

also i would not run the block more than .040 over and put a big rad in it with a 180 or 185 thermostat and maybe a 1 step colder plug, hard to say on that.

also, a proper timing curve is necessary.

i would not run pistons above the deck . . its just not sano, plus the gaskets are 90.00 a piece if you do that . . if your pistons can tolerste .020 off the top that is a way bretter way to go because you will also get some free rpm out of them because they are lighter.

you will likely need over .550 lift on the cam.

look at the K 1 crank and cast eagle and scat cranks . . if yiu havev money look st forged scat and eagles . . the k 1 is forged.
.

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83ttopgt

That combo puts them at .057 above deck. .040 off the pistons lets me use .060 head gaskets, but thats alot to mill off of them. If you google ".040 off trw L2379f40" you will see where its referenced. I don't see any other way other than custom pistons with a 1.6 compression height, with cleveland valve reliefs.

Any other ideas? or will it work?