I have a 1973 F100 2wd pickup. It has a factory upgraded 1978 351w and C6. I have done some things to it (listed below) and killed my bottom end. It idles and runs great and hauls butt on the top end but won't hardly even spin the tires in the rain! I think my issue is in my cam choice or the crappy smogger heads but please offer any educated advice on what I can do. I've had this truck this way for 3 years and it runs and sounds awesome but I'm ready for more power (torque)! Thanks!

1973 F100 with 1978 351w and C6

Detroit Locker and 4.11 ring and pinion

Stock converter and B&M Shift Improver Kit

Stock exhaust manifolds with true dual 2.5" custom to Xcellerator mufflers

Edelbrock Performer Dual Plane intake manifold

Edelbrock Performer 600 cfm carb

Pertronix Flamethrower Coil

Cloyes Gear 9-3135 Double Roller Timing Set --- Cloyes Gear 9-3135 - Cloyes Original True Roller Timing Sets - Overview - SummitRacing.com

MSD-8354 Ready to Run Distributor --- MSD Ignition 8354 - MSD Pro-Billet Ready-To-Run Distributors - Overview - SummitRacing.com

Crane Cams 36308-1 Valve Spring and Retainer Kit --- Crane Cams 36308-1 - Crane Valve Spring and Retainer Kits - Overview - SummitRacing.com

Comp Cams CL35-414-3 Cam/Lifter Kit --- COMP Cams CL35-414-3 - COMP Cams Magnum Hydraulic Cam and Lifter Kits - Overview - SummitRacing.com
<table class="overvw"><tbody><tr><td class="overvw-labels">Brand</td><td class="overvw-midmargin">
</td><td class="overvw-data">COMP Cams</td></tr><tr><td class="overvw-labels">Manufacturer's Part Number</td><td class="overvw-midmargin">
</td><td class="overvw-data">CL35-414-3</td></tr><tr><td class="overvw-labels">Part Type</td><td class="overvw-midmargin">
</td><td class="overvw-data">Camshaft and Lifter Kits</td></tr><tr><td class="overvw-labels">Product Line</td><td class="overvw-midmargin">
</td><td class="overvw-data">COMP Cams Magnum Hydraulic Cam and Lifter Kits</td></tr><tr><td class="overvw-labels">Summit Racing Part Number</td><td class="overvw-midmargin">
</td><td class="overvw-data">CCA-CL35-414-3</td></tr><tr><td class="overvw-labels">
</td><td class="overvw-midmargin">
</td><td class="overvw-data">
</td></tr><tr><td class="overvw-labels">Cam Style</td><td class="overvw-midmargin">
</td><td class="overvw-data">Hydraulic flat tappet</td></tr><tr><td class="overvw-labels">Basic Operating RPM Range</td><td class="overvw-midmargin">
</td><td class="overvw-data">1,800-5,800</td></tr><tr><td class="overvw-labels">Intake Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">224</td></tr><tr><td class="overvw-labels">Exhaust Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">224</td></tr><tr><td class="overvw-labels">Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">224 int./224 exh.</td></tr><tr><td class="overvw-labels">Advertised Intake Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">270</td></tr><tr><td class="overvw-labels">Advertised Exhaust Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">270</td></tr><tr><td class="overvw-labels">Advertised Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">270 int./270 exh.</td></tr><tr><td class="overvw-labels">Intake Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.500 in.</td></tr><tr><td class="overvw-labels">Exhaust Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.500 in.</td></tr><tr><td class="overvw-labels">Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.500 int./0.500 exh. lift</td></tr><tr><td class="overvw-labels">Lobe Separation (degrees)</td><td class="overvw-midmargin">
</td><td class="overvw-data">110</td></tr><tr><td class="overvw-labels">Intake Valve Lash</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.000 in.</td></tr><tr><td class="overvw-labels">Exhaust Valve Lash</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.000 in.</td></tr><tr><td class="overvw-labels">Grind Number</td><td class="overvw-midmargin">
</td><td class="overvw-data">FW 270H-10</td></tr><tr><td class="overvw-labels">Computer-Controlled Compatible</td><td class="overvw-midmargin">
</td><td class="overvw-data">No</td></tr><tr><td class="overvw-labels">Lifters Included</td><td class="overvw-midmargin">
</td><td class="overvw-data">Yes</td></tr><tr><td class="overvw-labels">Lifter Style</td><td class="overvw-midmargin">
</td><td class="overvw-data">Hydraulic flat tappet</td></tr></tbody></table>

 

part of your problem may be the intake.. the performers aren't that great.. i went from a performer to a victor jr and picked up quite a bit of low end power. i shaved 4/10ths off my 60ft time at the track and almost a full second off my 1/4 mile time.. your stock converter really isn't helping much either and a nice set of headers will help the exhaust flow

 

Thanks for the info! I was under the impression that a dual plane intake was better for low end power and all summit offers in the Victor Jr. is single plane? I know how and what a stall converter does but can you please explain to me why/how it will help the trucks low end torque? What cam are you running? Stock heads and pistons?

 

i'll try explaining it the way my dad explained it to me when i was younger..

basically, a higher stall speed converter is best used with a larger cam because it helps getting the cam into it's operating range before putting full force through the transmission.. so basically.. with a 2800 stall converter, you can put your foot on the brake and raise your RPMs to 2800 before the wheels will begin to try spinning.. that's the way he explained it to me

my motor was a stock bottom end (bore and stroke wise), 529/529 lift cam, edelbrock victor jr intake with a 600 edelbrock on top, stock (ported) E7 heads, 1.6 steel roller rockers, 2800 stall B&M converter, B&M shift kit, 4.10's and 38x12.50 TSL's.. the truck would get up and go from a stand still like the motor was under the hood of a mustang

 

well the stock manifolds arent helping you either. install some long tube headers and get an X pipe or H pipe on those duals. I would try some different heads and get the compression ratio up to at least 9-9.5 to 1. keep the intake you have and leave your tranny alone also for now.

 

The '78 heads and that cam are killing the low rpm power, as it stands compression ratio is about 8.5:1 and when combined with the cam you picked a high stall is needed to bypass everything below 2000rpm. But I don't like using a high stall on a street driven vehicle so I'd suggest changing the cam and heads instead, look for a set of GT40's off an Explorer or Lightning and put the comp cams 35-234-3 or 238-3 in it. Any yes the manifolds have to go too, longtubes will deliver the most low rpm TQ and peak HP but shorties will also be an improvement over the manifolds.

 

a 2800 B&M Street Fighter converter is extremely street friendly, but heads, headers and an upgraded intake will definitely do you good.. the better the air/fuel flow, the better.. your cam is a little large for manifolds and a performer

 

I thought GT40 heads were for EFI engines. What brand header do ya'll recommend? Will a header that fits a mustang or torino clear everything in my truck?

 

The $64,000 question is, how much can you afford to spend on heads? Paul is spot on about your compression ratio. You need something with 58cc chambers.

You might be able to get some shorty headers off a Mustang to fit, but you're a lot better off getting a pair or long tubes made for your truck. Hookers are pretty good for the bucks, or anything with 3/8" mounting flanges.

The Performer RPM manifold is much better than the Performer. More money down the rathole, though.

I don't think your cam is all that big for a 351, just get some heads with 58cc chambers and a pair of long tubes and you should be pretty happy.

 

Will GT40 heads work on my '78 351w? I read that these have 1.84 intake/1.54 exhaust which is considerably better than my stock smogger heads. Any modifications required to make them work since they are from an injected engine? Also, I have dual coil valve springs in my stock heads; will it be possible to put them on the GT40 heads? Will my stock manifolds bolt up to these heads?

I found a set for $150. Is this a good deal or would I be better off paying pull a part $30 and pulling them myself?
351 Ford Heads High Performance

Thanks for any advice!

 

Those 1970 351W heads are fairly good performers and can be much better with some
mild porting on the exhausr side. They have 1.84 and 1.54 valves which is pretty decent. The major drawback with any of these late 1960s and early 1970s heads is
the valve seats. As part of a fix up required on any of these old heads is the fact that
you will have to have hardened valve seats installed to be compatible with today's
unleaded gasoline. It will add quite a bit of cost to fixing these heads. You might want
to look at some other alternatives regarding cylinder heads.

 

There are no EFI specific heads in the SBF family they are all interchangable, on a small budget your best options would be rebuilt GT40's or some CNC ported E7's from Powerheads. Also look to see if you could find a deal on some used aftermarket heads, Eddy Performers or World Jr's are fairly common and go pretty cheap on the used market when guys step up to the better performing heads.