Here is a picture of the power curves from the dyno console. The torque curve has a big peak in it which probably is due to stack length tuning. The engine had very high VE at this point an wanted a lot more fuel than the normal Holley program provides. I ended up adding 50% extra fuel in this area from what the default program provided.

We just finished up a 463 (428 with 4.25 crank) with TFS heads and the Borla/Terminator X setup. It took several days to get the engine running due to problems with the Borla kit. They sent the wrong wiring harness, gave us the wrong info on the injectors, had the throttle bodies and linkage set up wrong, etc. But once we got all of the problems sorted out it ran fine. Made 550 hp and 620 torque with a very mild hyd roller cam. Should be a good street engine. Cost a ton of money. Customer probably has $30K invested in this engine but it what he wanted.

Just finished up a 428CJ street engine. Has a 4.250 crank in it so it is a 463. Used TFS heads and the customer wanted a Borla 8 stack setup with EFI. Has a Holley Terminator X ECU. Engine is very mild since the car is a street driver with overdrive. Small hyd roller cam. Made 550 hp on the dyno and 620 torque. Engine has a very pronounced torque curve, most likely due to the stacks. Expensive engine to build with the Borla setup.

There is an article on a FE build in Car Craft using these.  They appear clueless and sort of extroll the virtue of the raised pads.  "May require longer pushrods"

We're not clueless, the stock stand height worked just fine for us. That engine made 700 hp and everything looked great. Those heads are a super nice design as were the other parts we used on that engine. The engine took a little more "fine tuning" than a typical Chevy or Mopar engine, but you kind of expect it with a FE engine. Especially when using a bunch of brand new parts. We had one of the first sets of TF heads as well as set #1 of the Comp rocker arms so stuff did have to be tweaked a little bit but we didn't have to machine the stands. Pushrod clearance was tight in several spots and the intake did end up on the milling machine a couple of times.

I bought a '56 F-100 for $350 when I was 14. Took me a couple of years to save up enough money to buy a 351C from a '70 Mustang. I think I was 16 when I got it running. Had to fabricate some stuff but it wasn't a complicated swap if a 16 year old kid could do it. I did it in the driveway using my Dad's tools. He didn't have a lot, he wasn't a mechanic. I had to ride my bike into town to the machine shop to gets parts fabricated since all we had was a hacksaw and a 3/8 drill. I used the four speed from the Mustang but it would've been easier if I had used an automatic. Hooking up that passenger car four speed in the '56 required some fab work. Took me a while to get that all sorted out. By the time I was a senior in high school the truck was my daily driver. I also managed to win a fair number of street races in that thing. Didn't have a ton of traction off the line but it pulled hard once you got the tires hooked up.

My guess (based on 20 some odd years of dyno testing performance engines) is that the heads aren't great and the cam is too big. That is a fatal combination. The big cam kills the low end power and the heads kill the top end power. I just saw this recently where a guy had some "custom" heads and a huge by huge cam in his SBC. The heads were big but didn't work very well and the cam was way too big for the engine. We put a much smaller cam in the engine and picked up 100 hp. There wasn't much we could do with the heads since the guy didn't have the money to replace them.


I don't think we'll ever know the answer for this engine though since it would require a complete redo to test the theory. But if a guy came to me with that engine and a stack of money I'd put Trick Flow heads on it and use a much smaller cam.

Having a car that you spent a lot of money on but can't enjoy is no fun. I think you ended up with some race parts on a street car and if you aren't a really experienced tuner, that combo is often fatal to the project. There are lots of abandoned car projects due to the same type of issue. People get talked into cams that are too big or the wrong carb and then the car isn't fun to drive so it just sits.

Dual Holley carbs are going to be a bit tough to get sorted out on anything, especially if there is a large camshaft involved. If you insist on dual Holley carbs for the look then you'll want to talk to someone who has a setup that actually works. Vacuum secondaries is probably the way to go, and the smaller the carbs the better. Dual Edelbrock 500 carbs would be fairly easy to get to work but Ford purists would freak out. Personally I'd use dual throttle bodies on anything I wanted to start, run and drive on a regular basis.

Good luck and don't get too down on yourself. You should be able to sell the 660 carbs for some decent change to a drag racer. You'll need to call around to find someone who can setup dual Holley carbs for a street car. A wideband would be a good investment to make if you try it yourself. It is also a major time investment since the carbs need to come off to make changes and if you have metering plates in the rear then those need to be changed. If you tune it yourself you'll need a decent supply of parts so that is another investment to think about.

Yeah 240 duration would probably work just fine in that engine. I had a 470 inch pump gas engine in my car with a 236/236 solid flat tappet cam. That engine made 475 rwhp with an Edelbrock 800 carb and cast iron exhaust manifolds. It would scare the crap out of people when I floored it and grabbed the next gear. So I'm not sure why the guy put a 260 degree cam in a 431.

I put a 254/260 solid roller in that 482 inch engine I did for Car Craft. That engine ran nice on the dyno but I won't be surprised if the owner wants to go one size smaller once the car is on the street. The car I have now has 512 inches with a 246/246 hyd roller and I think next time I update the engine I'll go one step smaller on the cam.

Of course some of this has to do with age. I reduce my cam size by a degree or two every year as I get older. When I was in my 20's I was okay with a 260 cam but these days 240 is more than enough. I really don't need to keep rapping on the gas pedal at every stop light to clear the engine out like I did when I was in high school.