New 393w is kind of a dud...

[travis]

I built this for a buddy of mine, for his '82 Ford LTD 4 door. It was intended to be a sleeper...but it is still asleep...

.040" over 351w block, 3.85" Scat crank, rebuilt stock 351w rods, forged dished pistons 9.6-1 compression, .046" quench. Balanced.

D5AE 351w heads, stock 1.84/1.54 valves, lightly ported (trimmed a little off the pushrod pinch, blended the bowls and short turn, trimmed the guides, cleaned up the ports). Comp 986-16 springs, screw in studs, 1.6 roller rockers

FMS X303 cam, 224/224@.050, .542/.542 lift, 112 lsa, degreed in at a 107 ica, hydraulic roller (not my choice!)

Mustang 351 swap headers, 1 5/8" shortys to dual 2 1/2" full length exhaust out the back, no cats, H-pipe, dynomax super turbos

Performer 2181 intake, brand new Holley 750 vac sec (also tried a used 670 vac sec), high volume mechanical fuel pump, 3/8" line tank to carb

DUI HEI ignition

C-6 trans, fairly fresh with mild shift kit and a 2200 flash stall Hughes convertor. 2.73 peg leg (was planning on 3.55's but this thing has a funky rear end in it. Still researching options for this thing). Car weighs roughly 3600-3800 pounds.

The engine has about 3000 miles on it now, and runs great. Starts at the bump of the key and has just a touch of quiet rumpy idle at 800 rpms. Throttle response off idle is surprisingly sharp...it hits relatively hard right off idle but by 3000-3500 rpm its like you let off the gas by 25%. It revs cleanly to 5500 but it clearly isn't making power past 5K. We've tried moving the timing and jetting around, which so far has made practically no difference. I strapped on my old G-tech (LOL remember those?)...FWIW the old tired small cammed 351w that was in there before ran 15.30's at 90.xx mph. This 393 run a best so far of 14.77 at 92.33 mph. It clearly hits harder off the line but once its moving it barely feels stronger than the old 351.

My buddy is more concerned with 30-100 mph performance than he is 1/4 mile racing, and he drives the car a LOT as it is an almost daily driver. There's a good chance that the 2.73's will stay at this point since the car doesn't have OD, but he would really like to see high 13's. Is this going to be possible, without N2O? We had to use the performer intake due to hood clearance issues, but have an old torquer that *MAY* fit, although that may not be a better option.

Initially he was going to use some Trick Flow 170 heads, and the pistons have the dual valve reliefs, but budget issues at the time of the build meant he had to use the lower cost option.

Do you think a head change and possibly a better cam choice can put this thing into the high 13's? What cam and heads should we be looking at?

[cgarb]

I'm not trying to insult your intelligence but, have you verified that the throttle is going wide open when you mat the pedal to the floor? You would be surprised how many times I've seen this problem, somebody swaps carbs and suddenly its half a second slow and they are chasing their tail...then its like duh!

[travis]

That was the first thing I checked, and it is getting WOT. Also checked fuel pressure on a few of our test runs and it is still pushing 4.5 psi at the end of the 1/4 mile.

[cgarb]

The 2200 stall speed and 2.73 gears arent helping it any for sure. I would try to give it some gear, 3.55 gears would make it faster. Better heads and cam no doubt would help also. The FMS cams are really turds, I raced with a guy who had an X cam in a 331 and swapped to a custom grind Bullet hyd roller and picked up 3 tenths.

[Carnut1]

Travis, keep the dual plane, I like a tighter quench, the gears hurt but you have a decent amount of cubes so it should be fair till about 2800 rpm and the x cam starts working . A modern roller with a tighter lc would help all around. You didn' t mention exhaust which could be hurting quite a bit. Go through and graph the timing curve, you may be surprised at what you find. Valve springs are an issue on the x cam at least for me when I used them in the early 90's. I actually used bbc roller springs to pull 7000 rpm on a 306. It should not have even worked with stock rollers and Crower stainless rockers but it did. Any pictures or numbers from your heads? That may help as well. Thanks, Charlie

[travis]

I did not have the heads flowed, unfortunately. I also didn't get any pics of the ports. I didn't do much to the intake ports, but took quite a bit of iron out of the exhausts, particularly in the bowls and short turn, and of course removed the giant egr humps. I didn't spend a lot of time on these heads and my work was probably too conservative, but I've never ported these D5's before and wasn't sure where the thin spots was.

The thing will rev above 5500 easily enough, but its just making noise up there. We was shifting at 5400-5500 rpms and it got slower if you went higher.

This thing has a 8.5" rear end in it, and apparently there is NO aftermarket support which I find kind of strange, considering how many years and different cars ford used this rear end. The lowest factory gear set I could find was 3.42's but so far I haven't been able to locate any. Unfortunately this era of cars has all but disappeared in the salvage yards. Plus, nearly all came from the factory as peg legs. We are looking into a slightly later model LTD or crown vic with the 8.8. Lots more options there and lots of aftermarket support.

The torque is "decent", but even with 2.73's it should burn 1 of its 225/75-15 street tires forever...and it doesn't.

The timing is 14 initial, 34 total, with a 12* vac advance can. Timing all in by 2800.

He wanted to use the X cam because he had it, but I think we need to go a little smaller, tighter lsa, and a little exhaust split. I was thinking a comp XE270HR-12, but ground on a 108.

[Carnut1]

New cam will help, airspeed through the intake ports may be high after 5000 - 5500 rpm with that many cubes. Better kick down the intake duration a bit, tighten the lc a bit and concentrate on the torque those cubes can provide. Dead gears, fairly tight converter, heavy beast, low end torque needs a boost. Thanks, Charlie

[mag2555]

Your never gonna make any power above 4000 rpm with those size valves ( and port area) on top of that CID motor!
And the more Cam you stuff in it will only serve to narrow up on the power band that the motor does have, and with those street gears that a totally non productive situation!

[BigBlocksOnTop2]

4 door LTD (heavy), 2.73 gears, D5 heads and 112 lobe center on the cam. Mmmm.... By the way its a 395.

[Curtis Mc]

Based on that combination or engine parts, trans and rear, this all sounds about right. 400 inches, with that intake, head and exhaust combo is all done 5000-5200 but will spin up to the lifter and spring limit like you are seeing. A C6 is about as power hungry as it gets and that 2.7 isn't giving you any leverage.

Check out this starting combo by Brian Hafliger (he is on ST, forgot his user name) - smaller engine, with better intake, better heads, better cam (108 ground), better exhaust, and it 'only' makes 391 hp at 5,900 rpm. Obviously the article goes on to a better head, but its starting combo is a good yardstick for what I think you were trying to achieve.

http://www.hotrod.com/articles/build-a- ... 1-windsor/

[rfoll]

This sounds like the classic case of the vacuum secondaries not opening fast enough. Have you tried changing springs? I freshened up a 3310 once and used a different vacuum pot and regardless of which spring I used, it would never achieve full throttle. The car would jump off the line and then run out of steam.

[turdwilly]

First off - best quote ever! > " It was intended to be a sleeper...but it is still asleep..."

Your heads & especially the 1.84 valve are way too small to feed 393 cu in at any rpm over 3500-4000. Intake - ditto. 2.73 has no business in a performance application, unless you're going for a land speed record. And that's a lazy inefficient cam with yesterday's technology.

You could make the heads work much better by installing 1.94/1.60 valves with undercut stems, a good valve job & opening up the bowls. Exhaust port has room to expand also, & needs it - the factory port is like a soda straw & is insufficient for even 351 cu in, let alone 393. I'm not sure about your specific heads, but on the C9 heads I did decades ago I was able to open up the exhaust quite a bit.

If you make these improvements to the heads, go with a performer rpm intake. And while a custom cam is always optimum, there are also many much better shelf options available than what you have now, with more efficient modern lobe design. Milling the heads & tightening the piston-to-head to .040" to get the CR closer to 10:1 will improve torque. But more than anything, you need to find a funky gear for that funky rear.

[prairiehotrodder]

Build a mild combo and get mild results. It all adds up to that. You know what to do: start with gears, then maybe weight reduction, heads and cam.
Brian

[Amilcar]

A mildly ported stock heads, never will feed thouse cubes @ 5500rpm, should be closer on a 302.

[rp930]

Gears and stall are killing that thing.