I am about ready to renew my engine in my 1972 F250. I have it set up for towing and geared for my use. I can keep the engine between 2000 to 3000 RPM at any speed from 20 to 75 MPH - which is as fast as I will ever tow anything. I will be cruising 65 MPH at about 2600 RPM in high gear.

Fuel economy when running empty is an issue with me. I live near sea level, but often climb to 9,000 feet altitude pulling a 6 horse trailer or a heavy boat. Most of the hardest work the truck will be doing will happen between 4 and 5K feet. If it matters, I have a C6 which I will renew with heavy duty clutches before I do the engine.

I wish to build an engine with a power band between 1800 and 3,000 RPM. I started with a bone stock 390 2V and have added a 600 CFM Holly carb, and am now installing long tube headers which will dump into 3" sidepipes. I have a set of D2 heads which I will likely port myself - if porting will add any power at this low an RPM

Carl posted about cracks in the 1UB crankshaft for the 428, and stated that his machine shop claims detonation (pinging) was the main culprit. It was enough to scare me off adding the longer stroke crank, so I will be going with the stock bottom end.

I realize you guys are more interested in high performance engines built for racing - but I am hoping you would suggest a cam and a set of pistons for me. If it is not too much to ask, I would like to know the torque values at 1800, 2,000, 2500, and 3,000 RPM for this engine both running a stock cam/piston, and with whatever you suggest.

I value your opinions and thank you for your assistance.

Clint

 

My recomendation would be the Crane 901. Great tq from idle to 4500rpm. I am currently running this cam and am VERY pleased with it. I would not bother porting the heads for low-rpm usage. It will help power on the high end when you need the extra flow. I dont know what pistions to recommend I am running stockers, you could do the same with no problems. However, I have heard many say the Silvo-lites are very good.

 

The silvolite 1130's should work good and provide the proper compression ratio for the Crane 901 cam.

When I ran it through DD2k with stock unported heads, headers, and a 600cfm vacuum secondary carb, you get 312hp @ 4500rpm and 427ft-lbs @ 2500rpm.

 

Thanks Rusty, and Ford352. Three questions:
1. Is 427 @ 2500 the best I can do?
2. Any idea what it would be stock?
3. am I right in thinking the silvolite 1130's are 9 to 1 compression?

 

You can do better. If you port those stock heads the torque goes up to 433ft-lbs @ 3000rpm, but it also extends it out farther. This is reflected in increased hp. You'll get 351hp @ 5000rpm.

Stock FE was around 361ft-lbs @ 2000rpm, and 244hp @ 4000rpm. According to DD2k with stock head flow numbers and stock cam loaded in anyway.

I calculated the compression to around 9.4 with the 1130's.

 

Thanks a bunch - I'll start gathering the parts. I want to do the rebuild after Xmas - need to use the truck that week, plus want time to work out any bugs with the headers and tranny before I open up the engine.

 

427ftlbs is actually very impressive, espeically since its coming at 2500rpm.

 

Sure is - a 20 percent improvment over stock. And stock was pretty good.

 

I tend to agree with the posts above. It would make a good low end engine. Don't waste your time porting, it won't help a noticeable amount that low. Also, remember that the 428 was the engine ford made to torque their big heavy cars around. Don't be afraid to use a 428 crank, especially if you are after low end torque. On identical engines, I wouldn't be surprised to see a 30ft/lb or more difference from it. Over 5000 feet you'll need all the help you can get.

-Scouder

 

390 bottom end, silvolite pistons, unported D2 heads, C7AE car "S" 4V iron intake, 600 carb and 901 cam is what I'm running in my truck. I do alot of very heavy towing. 5000 ft is the highest elevation I've towed at and it was still very impressive. I run a manual with the same final drive in 4th as you have. The engine has a very broad power band, but it hits a wall at 4500 rpm. It holds it's own empty or loaded and manages 15 mpg freeway.

 

Thanks, Duston. That is very encouraging to hear. That stretch of I5 from Sacramento to Portland is probably about average for my type of driving, so I expect our driving conditions are about the same. I hope mine will perform as well as yours.

I have an Eaton 3 speed auxiliary transmission I have been saving in case I ever wanted to build a dual wheeled 1 ton that I can add if I need it. I don't think it would help in normal driving, but it does have a times 2 underdrive for starting and backing a heavy trailer. I worry about the torque converter overheating when moving slow.

 

Anybody know where I can order the silvolite pistons? The normal suppliers don't carry them, or at leist I did not find any online.

 

napaonline.com

 

debestuss, I could not find any silvolite parts listed on the napa website.

They did come up with the Clevite CEP2241831, which is a flattop piston. The Silvolite 1130 has a dish.

 

Run down to the local napa store. They should have 'em.