I am in the process of building a 393w. In trying to collect info. and parts to do this build up it has occured to me that by reading this forum and others that there really aren't a lot of people building this motor. My question is why??? Basically the only "specialty" part you have to buy is the crankshaft (although I guess you would have to say maybe heads are a requirement too).
I don't think the rod to stroke ratio is out of this world. Is it? I guess I am stumped.
If your willing to run a high compression ratio you can pick up a set of Sealed Power H273CP pistons for $80 (approx. 11.5:1 with 58cc heads).
When I decided to build the 393w I picked it because it was a lot of cube for not a lot of bucks. I'm on a budget and a stroked 5.0 cost much more if you want big cubes. Heck for the price of the pistons for a 5.0 stroker I bought my crank!

And now what I have and then some questions:
74 351w block
3.85 stroke crank
Keith Black KB364 pistons (9.5:1)
Oval head stock rods with ARP bolts
World Products Windsor Jr.'s 58cc
Screw in studs, guideplates, full roller rockers
Holley single plane intake
2 spd. Powerglide Auto
3500 stall
3400 pound car
3.08 gears but willing to change

This will be mostly a street machine. Rev limit about 6500rpm. I know the heads are not the best choice but I already have them and since I'm on a budget don't wanna fork out another $1500+ on something else. I will just have to use them for now and maybe upgrade someday if I hit the lottery. 500 streetable horsepower on pump fuel is the goal but I'll take what I can get

Questions:
How much lift will this setup safely handle without fly-cutting the pistons?
Any ideas on some cam spec.'s?
Single Pattern or Dual? ( I think these heads are fairly well balanced and are OK with single pattern....am I wrong?)
Here are a couple I have in mind:
(Good Price)Crane Energizer 284H 228@.050 .512 lift 112 lobe
Comp Cams Magn 280H 230@.050 .512 lift 110 lobe
Maybe should find something with more lift??
Ultimate carb. size is something like 721cfm. I want to run a vaccum secondary so do I go with a 700 or 750? Which one? (budget oriented....no all out race carb.'s)
Thanks guys!!

 

I'm enjoying my 393; a torque monster. Which style World Jr.'s do you have, cast or aluminum? Check out www.worldcastings.com to get a detailed description of your heads because they list many 58cc styles and then you can get a fix on your max. lift to pick your cam and if they turn out to be the roller style you will have to do the retrofit kit for your block or look for new heads. With your Keith Black 22cc dished pistons your compression ratio calculates to 10.1 and that is fine; my ratio is 10.8 and 93 octane is no problem. I'd go with the single plane intake and check out the speed demon carb website and you can email them your engine specs and they will suggest which CFM is best. 3.08 in the rear is alittle high; I'd lean toward 3.73 or 4.10. I'm running a 4.57 locker - cruise rpm is 2800 @ 55mph and it keeps on pulling to my 7000rpm redline. I planned my engine build for 2 years so do your homework and you want have any surprises.

 

Cast Iron. I have the spec. sheet that came with them and I believe they have .600 lift springs. I figured the valves might hit the piston before that but am not sure. I may eventually mock this up and actually measure the lift clearance.

 

you have a point aftermarket crank and stock rods with stock 302 pistons 30 overbore and there you have it 393 cubes. My guess is once you get to the point of preparing the build you realize that the stock heads suck and if you really wanna maximize your build your gonna need aftermarket heads or at least 500-700 dollar reworked stock early model head. still, not bad though when you think about it

 

jtaylor.... Yes that is sorta what I did. I originally thought about using GT40P heads that I had and then after studying a little more it was obvious that they would NOT be a very good head for this many cubes. I then decided to use the Windsor Jr.'s although a better head would produce more power these heads should suffice for awhile.

 

Why the single plane intake? I would think the performer rpm or better yet the stealth weiand would be better for low end street as well as high rpm hp. My brother has a weiand and it does it's job well. Just curious, good luck with your build

 

OK since you asked........... I already have the intake lying on the shelf so thought I'd try it. If I had to buy one your right I would definately look at the Performer RPM. Maybe I'll find someone that wants to trade locally before I get this thing together

 

Log on to www.trickflow.com and click on the article file on the left side of the home page. They did a 393 build with some great results and a complete list of parts used and the torque and horsepower numbers are big block killers. I based my build closely to this and only altered a few parts.

 

I kind of figured that to be the reason. Again good luck

 

How reliable is the 393? I am looking to upgrade my engine in the next year or two but I dont want to spend all kinds of money on an engine that wont live past 50k. Any ideas of the life line of one of these? Thanks in advance.

Bill

 

Just something to consider here, lots of people build motors for street use and thats great, but heres comom errors people make;
single plane for street: no , it a high rpm design, dual plan would be better, the single plane will scream 4k rpm up, but the dual will make better power 1500 rpm - 5500rmp
Exaust- 3" front to back ? NO! big mistake, people think the bigger the better, only true for high rpm , 2 to 2 1/2' tail pipes on free flowing system give you more mid range tork!
CAMS- comon mistake people over cam street motors, Shure they sould good and the motor will scream like hell at high RPM , but consider on a street drivin car/truck you be running between 2k and 4k rpm 85% of the time, so where do you want to make the most power?
3500 rpm stall? Thats a lot of Stall unless you planin on runing a BIG CAM witch would be over kill on the street. Just something to think about! Good luck with your motor! DW

 

DW2455 Thanks for the input. Actually some dyno tests show that GOOD single plane's will run just as good as a dual plane at low rpm's. It depends on the intake. Although you are right others are designed for high rpm ONLY. Oh and I already have the intake so I'm going to give it a try.......heck it's easy to change

 

Good luck with your motor, hope it turns out realy good for you! Keep us posted when you get it runing rite! DW

 

Up to your choice of drivetrain, it looks good. The powerglide is a good choice for a lightweight strip machine, but IMHO is a lousy street trans especially with a tall rear ratio like you have and a 3500rpm convertor is going to cook that trans in short order. A stock C4 has a lower 2.45:1 first gear and there are planetary gears that will take it down to 2.84:1. A 2.84:1 equipped C4 with a 3.25:1 rear ratio equals a 1.86:1 low gear Powerglide and a set of 4.96:1's in the rear. For a bit more money, you can get an AOD with a 2.84:1 first gear and, thanks to the overdrive, use rear ratios like 4.10:1 and lower.

 

What's wrong with overkill?!?! Just kidding. Point well taken. I think I will see if I can come up with a good street/strip C-4 tranny. I already have the PG and 3500 stall but it's starting to look expensive unless I try and make my own adapter. QS