I am considering options for swapping out my 300.

Originally it was stock 460, but swapping an entire drivetrain would not be fun.

I've decided to go with a 351w, but need more cubes, and would like the stock EFI.

Here's the question:

Will the factory computer and heads support roughly 380ft-lbs from 2000-3500rpm? I don't mind if the motor doesn't make any power above 4000rpm, this is going in the work truck and not a race car.

Looking at 393 and 408 strokers. The 408 interests me because it's a 4" stroke, and my 300 has a 3.98". I'd like to model the 300's powerband, and extend it by about 500rpm if possible.

Thanks!

 

The 393 is the more popular out of the 393/408...the 408 does have a little better rod ratio, the torque difference will be a little better out of the 408.

I was trying to decide between the 393 and 408. I got the 393 because it was I think $400 cheaper and 3.85 v 4" stroke isn't a big deal for me so I went with the 393. If you really want a torque monster, get a 427

The stock heads should be ported, or swapped from something else IMO. You'll be really choking performance with stock heads. I got some cheap performance heads.

You'll have to talk to Comp Cams for a cam recommendation for the type of power you're looking for, probably close to an RV cam.

You'll need to use MAF EFI, and even then you will probably need tuning done to the EFI, either by a dyno or custom tuning software that you do yourself.

I'll be hitting the dyno for the 2nd time on saturday to get my tuning/chip for my EFI on the 393. I can show you the dyno graph of what my motor makes for power.

 

mustangGT, thanks for the info.

I'll probably go with a 393 so that i have a larger choice of pistons for the right compression. I'd like to run it on the cheap stuff. Obviously this build is going to be very mild.

The 302 computer and harness fits the 351w, correct? Aren't there two different firing orders for the 302 motor?

From my limited knowledge of these windsor motors, am i correct in thinking that if i get a stock MAF ecu/harness/heads from a 302HO of some sort, this will fit on the 393?

 

Just out of curiosity, what does it cost per session to have tuning/dyno testing done. I was debating having a custom tune done after I get my new heads and cam, maybe intake also. Assuming I can find someone locally to do it.

 

My 393 has forged 302 pistons. If you keep compression down, and the timing right, it'll run on 87 just fine. Mine is at 9.5:1 compression and I think once I get it tuned right and timing set right I may also be able to run 87 or 89 rather than 93.

A 302 MAF computer will run the 351/393, my computer is a 302 mustang computer, with the FMS MAf conversion kit. But it won't run it perfectly, so ya gotta get it tuned.


I would say that you could run the stock 302 MAF computer, heads, wiring, will fir the 393. I don't have a lot of time at the moment to write a lot of info but I'll check back later on today and offer up some more.

I can get 3 dyno pulls plus a custom chip for $400. It's $75-$100 for 3 dyno runs w/o the chip. Some places charge differently, but it's SCT dyno tuning on a dynojet that I'm doing.

SCTflash.com I think is the site, and they have a "dealer locator".

 

Out of curiosity, what brand of piston did you go with?

 

If you can find a stock mass air truck in your matching configuration (transmission mainly) from a '94 or '95, the harness should plug right into your truck. The firing order would match and it would be wired for sequential injection too.

 

I went with a Coast High Performance (CHP) 393 shortblock. It has their brand of Probe forged racing pistons. I like them, I've read good reviews of them across the board and they have deep valve reliefs for a big cam. I can move up to a bigger cam and not run into clearance issues.

I have one suggestion. Since your building a very mild motor keep the future in mind. Invest in a good bottom end and make it so that you can easily upgrade it in the future if you choose to do so.

My shortblock is not the best but it's pretty damn good and my options are still very wide open. I could shoot nitrous or move to a supercharger....or just do more mods to it and get more power out of it. I know the bottom end would take it and I'm leaving myself the opportunity to go bigger. That way I have the option of changing things without going through hoops to do so.

 

MustangGT, that was the plan.

I appreciate all your help and suggestions.

EPNCSU- i have a 300, so i might be missing a couple plugs...

 

I suggest porting those stock heads and trying to get a bit more flow out of them. That 393/408 will be really sucking hard for air with those stock heads. One time I called Ford about my motor and in conversation I mentioned the GT-40Y heads that I have. They're a mid level head, but he commented on it being a little small. But I told him the reason why was for torque and he said oh ok. So if mine choke it a bit, i can imagine stock heads would really choke it.

Wouldn't hurt it though.

 

Porting is a definite.

I would be doing it myself however, so it would mostly be smoothing out any casting marks, blending the bowls a bit, and smoothing the valve guide bosses. Then i would go and port match the intake to the head, and of course polish up those exhaust ports after smoothing.

 

Sounds like you're on the right track...

 

For my situation, I'm not building a mild motor. I've already bought the forged (not cast) 393 crankshaft from Ford Motorsport. I had posted earlier about wanting a 351W 4-bolt main that nobody seems to make. I know the sportsman block is tough, but you think Ford could have spent a couple of bucks more to build a 4-bolt main 351W. (Still checking if World makes this block. Prolly not.....) I'm also going with AFR heads. I want this built for high RPMs. I guess I hadn't heard of that brand of pistons. They sound like they are worth checking into.

 

Look into a Dart block. It's what most use for high performance. The sportsman blocks are ok but not all that much stronger than a stock block I'm told.

You can get a good 500-600 horse out of a stock windsor block without trouble.