I just bought this truck and need some help
1Can i use an older 460 such as a 74 and still use the efi?
2Also is there anything i can do during the rebuild for better milage and torque,it will be used to pull my camper.
Thanks
Gregg

 

1. You can use a older shortblock but you'll need to reuse the EFI heads, intake, and throttle body.
I wouldn't go to an aftermarket setup unless you like spending money, it wouldn't gain you much without a lot of other modifications

2.You can build for more torque but there is not a lot you can do for mileage. After reading this site for the past couple of years I'd say the average mileage from a EFI 460 will be 11-12 MPG empty and 7-8 MPG towing depending on tow weight. The best value per dollar will be a set of headers and dual exhaust coupled with a K&N air filter. Next would be a cam change but you need to keep it MILD. I'd say do not run more than 204 to 206 degress duaration @ .050 on the intake and 214-218 on the exhaust side. Even those figures will kill bottom end way down low (1200-1500 RPM). Most people would not feel the loss at that low RPM but you will feel it if your towing 8000-9000 lbs. like I do.

3. What is your gearing? A 3:55 butt gear works great up to 5,000-6,000 lb.s trailer weight. But if you do a lot of hill climbing with over 6000 lbs. I'd go with the 4:11's. I can pull a steep long grade at 50-55 MPH (5000 ft. elevation) since I put the 4.11's in and only lost half (0.5) MPG. I average 8.0 MPG towing.

Deen

 

The truck has 3.55 gears,and a c-6.I belive these will be alright for now.I guess ill go back with stock cam but add headers and duals.What brand of headers are you running and did they fit ok?
Thanks,
Gregg

 

Get a set of L & L headers. They aren't the cheapest out there but are deffinitly worth the money.

 

I run Headmans, they are around $200 mail-order. A lot of people say they don't like them since they say they don't seal well, but I use copper exhaust gaskets and haven't had a leak in over two and a half years. The fit was perfect and no modifications had to be made other than adding a dual exhaust system. You do want your muffler shop to save the O2 bung and weld it back into your new exhaust system. The O2 sensor helps fine-tune your EFI injection.
P.S. Another advantage of copper exhaust gaskets: they are re-usable.
Deen