I have read on here many times that with a 393 stroker crank you can run stock 351W rods with 302 pistons but there hasn't been much detail. When selecting a piston will the advertised compression for the 302 be the same as the 393. If I wanted 10:1 compression for a 393 what advertised compression 302 piston would I look for?

 

Look around online at some of the kits.........

10to1 would be easy.....

Same chamber size with a lot more stroke, most 302 pistons used in a 393 have big dishes in them to bring the compression down.


Also look around for compression calculators, they are everywhere online.

use 3.85 stroke, 4 inch bore, 60 cc chamber, .041 head gasket thickness, .014 to .021 deck height, and then whatever piston...most stock 302 pistons are 3 to 6 cc dish most 393 strokers are 22 cc dish if I'm not mistaken.....and if I am someone will correct me.

 

you would have to run premium fuel all the time, probably even have to run aluminum heads, what rig are you doing this to?

 

I am not sure yet if I will even build one. I am just doing some pricing and research right now. I would like to start with a Windsor block, use a 393 crank and bore it out to a 400 (.060) with 2bbl Clevelend heads. I am trying to find out if I can use 302 Clevor pistons with the stock rods and not have something like 12:1 compression. The Federal Mogul 302 Clevor pistons are listed at being 9:1 with the 76cc heads. I don't think I would want anymore than 10:1. Is there a way of doing this without spending big money on rods? Could I just find the appropriate compression pistons and have them cut for the valve relieves?

 

what vehicle is the motor planned for?

 

I had a set of those 302 clevor piston...wish I still had them, they don't make them anymore. I think when I was going to build a 393Clevor with those pistons it was 11.?to1

you will have to go with a custom piston...or cut some 22cc?? dish 302 pistons for the cantered valves.

 

I am planning this build for my Mustang. I will look into the dished pistons and get a price on having them cut. If everything fits my budget I will build a 400 Clevor. I am looking for more torque than peak horsepower so I'll be happy with anything from 9-10 compression. I started another thread a few days ago where I stated I had ordered the 351 Clevor pistons- but since then I got a phone call saying that the pistons were out of production and I can only get a set if another warehouse has them in stock. So I figure that since those plans were wrecked I might as well go bigger. The crank I can get for not much more than a stock exchange. I also decided to go carburated and I will purchase the Edelbrock intake after it is available. The intake is priced the same as the adapters to use an EFI intake. I just want to tell people that I have a 400 in my Mustang when they ask. That'll confuse them, especially when they see the 400 (Cleveland) top end.

 

if you don't deck the block or plane the heads you might get away with just a small notch in the piston...near the exhaust valve. A torque cam will have a short duration and smaller lift than say mine. 248@.050 600 lift.....so you might be able to sneak a set of dished 302 pistons in there.....look for a set with the short pin height, they had three 1.5?? 1.603? and 1.615? I think....something like that. Plus you have the smaller valves.

Get all the parts and start mocking it up..... You'll have a blast..

I would leave the intake port as is and just port the roof and blend the bowls on the exhaust side. Should be a killer truck motor....to bad you couldn't run a 351W rpm intake....

 

PAW has an engine that can be had as a shortblock you add your own heads to ($2500) or a longblock.

The crank is a re-machined 400 or 460 crank, fitted with Chryseler rods, and a Kieth Black version of GM pistons that ends up a 427 WINDSOR...

The compression is modified by the location of the wrist pin boss machining point, but I recall mention of nine to one with open chamber heads, and 10 or 11 with quench.

In the process, the block must be clearanced to make room for the counterweights, and as far as I know it can be ordered as a four bolt main cap machine.

That one is about the most wicked build I have heard of recently, due to the weight savings over the Clevester.

The bore and stroke were very close to 4" by 4" - if I remember right the bore is something like 4.175

 

Thanks for all the help. I'm going to select a set of pistons tomorrow at work and I will probably order my crank.

 

friend of mine bought that same kit from PAW he used a set of ported 78 (I think) they had huge chambers 69cc I think with 1.90 1.60 valves. He ran it in a boat, from what I heard it was a runner......But it was the same kit just 2 bolt block.

 

http://store.summitracing.com/partde...3&autoview=sku
How do you think this cam would work with my setup?
What size of carb should I be looking for? I am thinking about a 700 but I am new to carbs.

 

thats going to be 533 540 lift with 1.73 rockers......on a 214 224 duration @ .050 almost like a roller....might be to much for it.....I don't know....

I would call a cam company.......

 

Sounds bitchen - I bet it ran like a raped ape!

 

In the Sealed Power catalog they list the 393 stroker piston with a .060 dish. I am not sure what this would measure in CCs. The compression ratio is 9.69:1 with 69cc heads so I am assuming that with 76cc heads I would be around 9:1. I think I will order these pistons and relieve them for the cantered valves myself. I would like to use flat top pistons and be closer to 10:1 but I probably couldn't modify the pistons that much.