Anyone "Tweaking" the Ford 392 crate?

TerrysSPF · #1 (**permalink**) 10-03-2003, 11:08 AM

Has anyone done anything to the Ford 392 crate engine to get some more HP out of it? I know it comes with GT-40X alum heads and they say you can port match the heads with the manifold for a little better flow. How about porting the heads themselves, or going with AFR heads? Supposedly the intake is a copy of the Edelbrock Vic Jr., so as long as it flows the same, there's probably no reason to change it. How about a cam change? Has anyone tried something bigger than a 750 carb on it? Ford says you can mill the heads up to 0.050-inch. -good for about a 4-5% HP gain, but that would raise the comp. ratio to the high 10's (about 10.7:1). May need a little octane boost at that?
They are said to be good for 430-450 HP "as is". They have become a very popular choice for Cobra rollers and supossedly a pretty reliable engine (although I've heard a couple people mention "oil problems" with them.....mostly leaking from the rear of the manifold and easily fixed).
I'm seeing a lot of used SPF's (and other mfg's) with this engine installed. I've always said that when the time comes for me to get a car, I would want it to have at least 500HP. I've never driven one with the 392 crate so I can't comment on the performance. I've driven cars with a 408 built by Perf. Engineering with 510HP and one with their 418 / 540HP and they were good for getting the heart rate up! ..... but I drove one with the 351 / 385HP crate and it wasn't enough power (especially after driving the others FIRST). I still have yet to drive a BB car, so all this may be moot if I drive one and LOVE it, but BB cars are usually a little more $$, and I'm looking to get the most bang for the buck.
So, has anyone squeezed more power out of the 392 crate, or have any ideas on how to do so?

John A. Simpson · #2 (**permalink**) 10-03-2003, 06:14 PM

You need to check out some back issues of Muscle Mustangs & Fast Fords magazine regarding the 392. In the November 2000 issue they changed to AFR 185 heads and with no other changes got 537 hp at 5900 RPM and 505 lbs-ft torque at 4900 RPM. If you are going to change oil pans you might think about getting the short block and adding the AFR heads yourself, etc. Look at the May 2003 and June 2003 issues for another 392 that produced 506 hp and 515 tq with a little milder cam. I'm with you, I afraid a hot 351 won't quite cut the mustard.

TerrysSPF · #3 (**permalink**) 10-04-2003, 06:42 PM

John: Thanks for the info!
I don't think they were working on a Ford 392 crate engine though in the 2000 mag. because it wasn't avaliable yet. I have the Winter 2002 Hot Rod Engines mag and they tested the engine then and it was brand new (just out). I'll check out some of the Ford mags you mentioned and see what I can find. I know AFR makes great SB Ford heads and would think either the 185's or even the 205's would make a pretty good increase in power.

Fred Douglass · #4 (**permalink**) 10-04-2003, 07:09 PM

..I for one agree that the more power the better---you don't HAVE to use it all the time---but it's nice to have it there! I am trying to get a 408 Cleveland going well. These things are air-drills, when it comes to revability. I just wnated to get over 450 hp AND ft/lbs.
An old gentleman told me some "truths" which may or may not still apply. He said you want to keep the cubic inches and the desired power numbers (hp and torque) roughly equal or no more than 25% OVER the cubic-inch displacement. If I'm getting 408 ci, I should expect a 500 hp. 500 ft/lb build will last quite a while before the rebuild. THe old man said it is less stressful to build street engines this way....
I've driven three SPFs on test drives---one of them had a stock 394 "crater"--good power, smooth engine--but not enough for me. The second one had a 427 (from a 351W) and it screamed. The third had a punched and stroked 429--up to about 511 ci (no crap) and that car was SICK. WSith that much power, you don't care that the plant weighs 200# more than the Windsor stroker--you ain't gonna notice it. That car scared me!

You will find that these cars "teach" you a lot (hopefully in an exhilirating and damage-free manner). What will happen, when you get "used" to your 450 hp engine is that you'll want MORE---I certainly did!

bnewell · #5 (**permalink**) 10-04-2003, 07:15 PM

Terry ~ don't second guess yourself.....buy the BIG BLOCK and be done with it

Brian

TerrysSPF · #6 (**permalink**) 10-04-2003, 09:14 PM

Brian: I know, I know.........go for the BB (my wallet is telling me otherwise!).. Can you believe I STILL haven't found a BB car to drive!? (Although I've been busy most of the summer and haven't been looking that hard). I'm trying to get ahold of our buddy down the street from me to see if I can get a ride. I've been so busy this summer I haven't talked to him (or got to chase that little white ball around like we talked about!).
I can't believe nobody has "played" with the 392 crate engines around here! I'm wondering what a set of AFR heads would do, or a full porting of the GT-40X heads that are on it. Someone has to know SOMETHING!!!??? Help!!!

John A. Simpson · #7 (**permalink**) 10-04-2003, 09:27 PM

Just changing from the GT-40X heads they picked up 75 HP! They tried a different cam in one article same issue, just moved the hp up the rpm band, more than they thought the engine would like on a regular basis.

OneFastRide · #8 (**permalink**) 10-04-2003, 09:30 PM

Terry -
I bought an SPF with a 392 crate 2 years ago. I have since replaced the GT40 heads with Trick Flow Twisted Wedge heads. I replaced the 750 vacuum advance Holley with an 820cfm AED Dominator with mechanical secondaries.
That's it. This car is very streetable. I have put almost 20,000 mi. on it. On Labor day I took it to the local drag strip. With Yokahama 295/50s on the rear and @ 18lbs of pressure I ran and 11.89 / 120.5 mph. That should give you some idea of what a slightly tricked 392 crate can do.
Best Regards,
Steve

TerrysSPF · #9 (**permalink**) 10-04-2003, 09:43 PM

Now we're getting somewhere!
John: AFR makes some great SB heads, and if you could add 75HP with the 185's, then I wonder what the 205's would do! I'll see if I can look up that article, but I'm almost certain that the 392 crate that you buy direct from Ford (or other suppliers) wasn't offered in 2000. Maybe it was a different engine they were playing with, but if it had GT-40X heads, then it at least gives me an idea on what a head change would do.

Steve: Thanks for using your 1st post to help me out! Welcome to the Club! The person with this engine replaced the 750 Holley already, with a 750 Demon carb and he said it made a difference. Did you keep the stock intake on?

OneFastRide · #10 (**permalink**) 10-04-2003, 10:36 PM

Terry,
My engine install and the subsequent head change was done by Olthoff Racing.
The Olthoff's put the dual plane intakes on their crate installs, and that's what I've always had. This engine is making peak horsepower at low rpm -5800 to 6000. A definite plus in my book. A downside is that it does NOT like 92 octane since the head change . I burn 100 octane street legal race gas. At $3.49 a gallon and around 9.5 mpg, it's not cheap fun, but I'm not compaining!
Steve