Author Topic: 390  (Read 6166 times)

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RP

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390
« on: May 10, 2011, 12:38:17 PM »
It appears from Jays book on larger displacement FE engines, and from the other forums, that a std 390 GT from '66 on is a pretty anemic unit.

The stock GT intake and exhaust manifolds, as seen in Jays tests, would seem to limit them to 275 hp at 4800 rpm.
The 352 is just 40 hp shorter.

It appears that it is almost mandatory to install a decent set of headers and a good intake to get the 390GT close to Ford's advertised hp levels of 315-335 hp @ 5000.
How much does a solid lifter cam like the 270S  affect the output? 5700 rpm and more hp yet?
Are there any dyno tests hiding at jay's supporting 390's?


I am amazed how the stroker kit wakes the FE up; 400+ hp seems to be just about assured as the huge inches tame wilder cams, and the new rods seem to be a blessing for reliability.
 





jayb

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Re: 390
« Reply #1 on: May 11, 2011, 07:31:08 AM »
The 390 GT engine was a pretty anemic engine, and didn't do Ford's reputation any good back in the 60s.  I'm not sure where you come up with the intake and exhaust manifolds limiting power on the engine to 275 HP though; can you explain your reasoning?  I don't think that the stock HP ratings are unachievable with the S intake and the 390 GT exhaust manifolds, although I can't say I've ever dynoed a stock 390 GT engine.

I only have good dyno data on one stock bore/stroke 390; almost all the people that I know who've built these engines turn to a stroker kit, for the reasons that you specified in your post.  The 390 I tested had C6AE-R heads that were given a mild porting job, so that they flowed about like 428CJ heads.  It had a 270S Comp solid cam, Performer RPM intake, a 600 cfm carb, and the truck headers.  It made just at 400 HP and 440 lb-ft of torque.
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC

   

RP

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Re: 390
« Reply #2 on: May 11, 2011, 10:49:32 AM »
It is possible I shortchanged the GT.

I was actually using some of the data from your book on the GT exhaust and the S manifold.

The closest I could interpolate was your 428 T bird engine with the GT exhaust, using a decent intake, and then the same engine with the S intake and the dyno headers.

Taking both, deducting a bit for the 40 ci less displacement, results in a pretty low hp unit. It may be more than the 275, but I realize that few shops actually old stock engines!

I agree that waking up the 390 is certainly a case of intake and exhaust.

The old solid lifter 330 hp unit that a friends 63 Galaxie Fastback had is a far cry from the stock GT. It had the good iron manifolds and C3 Iron Intake.
So based upon your test data, and that engine, is why I figure the 390 GT was pretty anemic.

50 hp or so is on the table, with simple changes to a 390. I was amazed how even the Performer 390 was such an improvement over the "S", and using FPA headers had to bring you to 325 hp or so.

TorinoBP88

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Re: 390 - Tune up w/ stock parts.
« Reply #3 on: May 11, 2011, 11:06:43 AM »
As Jay noted, and i have done myself, a little time detailing 390 GT heads, Truck heads (D2T) or C6 heads can easily get you into the mid 350 HP range and with a LOT of torque as Jay noted.  Also, some details you must remember to follow though on: zero deck the pistons, carefully work around the cylinder head bowls and chambers, re-curve the stock distributor for more initial advance (12 to 18*) and a total of 34* to 36* range, get stock adjustable rockers if you can, get your cam, crank and rod clearances right, use ARP rod bolts and re-size the big ends, consider lighter forged pistons, run an extra quart of oil in the pan to ensure it does not starve at high RPM on on acceleration, degree your camshaft so you know if your straight up or advanced and are NOT just guessing based on spec sheets... that only works about 30% of the time. 

If your really want to go the next step, install a 4 speed TL or a TKO 600... that will make the power more fun IMHO.

RP

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Re: 390
« Reply #4 on: May 12, 2011, 09:55:04 AM »
I am finally putting together a replacement engine for my '66 Fairlane GT.
390, 75 cc C6AE-r heads. Rebuilt short block is together. Flat top .040 over.
I have three other blocks in a growing collection of parts, one of which will likely get a stroker kit, but this one will be a typical 390 build.

I have an alum 406 Ford Intake and a like new, performer 390 to choose from.
Both are about 15-20 hp down from a CJ or Perf RPM, at peak, according to Jays book. I have no "S" intake.

I am using a 270 S cam.

I was going to use the Stock 390 GT ex manifolds, but I will have to bite the bullet for FPA's.

The Goal is to come up with a reasonably streetable engine with at least 325 hp, the reason for my concern about the 390 power output, stock.

Jay's T bird engine from his book, was a similar build, but 38 ci larger.


 

cammerfe

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Re: 390
« Reply #5 on: May 17, 2011, 01:48:32 PM »
'Back in the day', it was fashionable to sneer at the 390. Brother Lon's '63 Gal convertible had a few detail changes, including a set of 406 short exhaust manifolds. It took that much work, and the replacement of the valve springs and lifters, to be able to best the typical 327 chibbie.

On the other hand, I had no trouble, with a 397 inch PI engine and modern replacement parts, going past 500 both on the Hp side, and Tq as well. I asked Comp Cams for a roller with the street manners of the 'AA' that came in my '64 'R' Code. It worked.

With the costs of stroker cranks, rods, and pistons falling so close to the cost of factory stuff, it now makes no sense not to go up in the CID department. But don't short the possibilities of the standard size 390!

KS

Barry_R

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Re: 390
« Reply #6 on: May 17, 2011, 07:00:27 PM »
I dyno'd something pretty close to a basic hopped up 390 a while back.  With a real timid hyd cam, a Performer RPM, and a set of off the shelf Edelbrock heads it made around 352 horsepower - running open through headers on the dyno.  Not bad - but still nothing to get too excited about these days.  No way was it anywhere near the rated numbers with iron exhausts and stock heads.

TX69F100

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Re: 390
« Reply #7 on: May 19, 2011, 09:55:02 AM »
I dyno'd something pretty close to a basic hopped up 390 a while back.  With a real timid hyd cam, a Performer RPM, and a set of off the shelf Edelbrock heads it made around 352 horsepower - running open through headers on the dyno.  Not bad - but still nothing to get too excited about these days.  No way was it anywhere near the rated numbers with iron exhausts and stock heads.

Barry,

Just how timid was that cam?
Brent
1969 F100 390/C6

AlexS

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Re: 390
« Reply #8 on: June 06, 2011, 06:42:07 PM »
The 390 GT engine was a pretty anemic engine, and didn't do Ford's reputation any good back in the 60s.  I'm not sure where you come up with the intake and exhaust manifolds limiting power on the engine to 275 HP though; can you explain your reasoning?  I don't think that the stock HP ratings are unachievable with the S intake and the 390 GT exhaust manifolds, although I can't say I've ever dynoed a stock 390 GT engine.

I only have good dyno data on one stock bore/stroke 390; almost all the people that I know who've built these engines turn to a stroker kit, for the reasons that you specified in your post.  The 390 I tested had C6AE-R heads that were given a mild porting job, so that they flowed about like 428CJ heads.  It had a 270S Comp solid cam, Performer RPM intake, a 600 cfm carb, and the truck headers.  It made just at 400 HP and 440 lb-ft of torque.

Jay I believe you are talking about my motor, if so Im actually running  C8AE-H Truck heads from a 360 out of a 72 half ton truck, It was a little more then a mild port job though. I found my flow sheets and my Intake flow number on the one port with the little bump up in it was 242.40cfm at 0.500 lift, we aren't exactly sure how much that bump affects the flow but we were guessing the others were around 248cfm at 0.500, I was hoping he was going to flow them closer to 0.600 lift because as fast as the numbers rose as lift increased they would have probably flowed 248-250cfm just by increasing the lift 0.050 even on the bad port.
The Exhaust flowed 206.72cfm at 0.500 lift, and probably would have been closer to 212cfm.  We could have gotten more out of them with a little more port work but this is where we stopped. This was also using the stainless steel 428 Edelbrock valves and springs, These are the ones that came in the Performer RPM heads, then I did a 3 angle grind on the intakes and a two angle grind on the exhaust valves. My Iron truck heads flow about the same as stock aluminum Edelbrock performer RPM heads on the intake and the exhaust actually flows better then the performer heads.

I would really like to know what the HP numbers are now with the Holley 830 Annular carb. Switching from the 600 double pump to the 830 was a pretty noticeable difference along with better throttle response and slightly better gas mileage when driving nice, its not even properly tuned yet, just bolt on strait out of the box and it doesn't seem to run rich even on the warm days, infact it was running a bit lean when it was cooler out. Do you still have my dyno data with your 750, or was it the 800? I never got copies of my dyno sheets.
« Last Edit: June 06, 2011, 08:56:38 PM by AlexS »


jayb

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Re: 390
« Reply #9 on: June 07, 2011, 07:47:49 AM »
Thanks for the correction Alex, for some reason I had it in my head that you were using C6AE-R heads.  I would call your porting job mild, but then my "mild" might be your "extensive".  Your heads do flow about the same on the intake as stock Cobra Jet heads with the CJ-sized valves and the port work.

On the dyno we used my 750 double pumper carb.  I save all my dyno data, so if you want copies of it just stop by sometime and we'll dig it up. 
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC