Why aren't more 393's built?
Posting Guru
Joined: Mar 2002
Posts: 2,070
Likes: 2
From: Boise, Idaho
Why aren't more 393's built?
Originally posted by quentrm250
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.
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.
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?)
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.
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.
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?)
Have you considered using a retro-fit roller cam conversion?
Thread Starter
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Junior User
Joined: Jul 2003
Posts: 57
Likes: 0
From: Southeast Nebraska
Why aren't more 393's built?
I thought about the roller cam conversion but by the time you get roller lifters, the conversion kit, a cam, and shorter pushrods your talking roughly $400. Believe it or not this was suppose to be a budget motor even though I have exceeded $2000 already! Arghhh!
As far as the GT40P heads goes........I already have a set. Not sure where you got your info. but MM&FF is doing a comparison test on 20+ sets of smallblock ford heads right now and the Windsor Jr.'s outflow the GT40P's by a decent margin. Not to mention headers for the GT40P heads are almost double what they cost for the Windsor Jr.'s which have the common pattern.
As far as the GT40P heads goes........I already have a set. Not sure where you got your info. but MM&FF is doing a comparison test on 20+ sets of smallblock ford heads right now and the Windsor Jr.'s outflow the GT40P's by a decent margin. Not to mention headers for the GT40P heads are almost double what they cost for the Windsor Jr.'s which have the common pattern.
Posting Guru
Joined: Mar 2002
Posts: 2,070
Likes: 2
From: Boise, Idaho
Why aren't more 393's built?
I don't doubt that the Windsor Jr's have a higher peak airflow, but the GT40p heads have more airflow at lower lifts. Plus the GT40p heads have better combustion chambers. I bought mine for $99 for the pair (bare).
WRT the roller cam conversion, I bought lifters on ebay for cheap and the spider and H-bars from the classified forum on corral.net for cheap. The reduced-base-circle cam is the expensive part but it would be a custom piece tailored to your engine.
WRT the roller cam conversion, I bought lifters on ebay for cheap and the spider and H-bars from the classified forum on corral.net for cheap. The reduced-base-circle cam is the expensive part but it would be a custom piece tailored to your engine.
Thread Starter
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Junior User
Joined: Jul 2003
Posts: 57
Likes: 0
From: Southeast Nebraska
Why aren't more 393's built?
On the GT40P vs Windsor Jr. comparison. You are somewhat correct to an extent. The Jr. doesn't outflow the 40P until .400 to .550 on the intake and from .300 to .550 on the exhaust. I like the fact that the Jr. has a better balance of intake/exhaust flow and also the fact that when using over .400int and .300exh lifts I will get more flow. I plan on using a cam that will have over .500 lift and feel the Jr. heads will help the motor benefit more. I think this might be very important on a big cube motor such as the 393. In reality both the Jr. and the 40P head are probably too small and I may be looking at updating the heads in the future, but I already have the Jr.'s so am going to try to use them for now. If anyone would like to trade a set of AFR 225's straight up for a Brand new set of Windsor Jr.'s.......EMAIL ME RIGHT AWAY! 
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