Help me map out my 351W!

[Freshmeat]

Merc- would the GT-40s be safe with high-comp pistons? Would I still be looking to have them reworked with new valves or are they okay as-is?

I'm still learning about what makes better horsepower and what makes better torque. Again, thanks!

[Mercracer]

Merc- would the GT-40s be safe with high-comp pistons? Would I still be looking to have them reworked with new valves or are they okay as-is?

I'm still learning about what makes better horsepower and what makes better torque. Again, thanks!

Why would you be worried about high compression? Flat tops is all you need for your application. Stock valves with good springs is all you need.

[Mercracer]

I'm still learning about what makes better horsepower and what makes better torque.

It takes torque to make horsepower. You want the maximum torque within your desired RPM operating range. This is true for any engine.

[Freshmeat]

Flat tops is what I'm planning for the 10:1- guy at the shop said they'll give me 9.9-10.1:1 CR, so that's what I'm doing... but would the valves clear that? I know the torque cam won't have as tall a profile...

[phayzer5]

most aftermarket pistons will have valves reliefs designed for high lift cams, so you should be fine with what your building

[mrltd]

used GT40's can be found cheap on corral usually. Most of them are 400 and under.


And I have a set of 66 289 2V heads sitting in my basement. Need alot of work though.

[Freshmeat]

Okay. So, I'll plan for GT-40s. Do I port them? Do I increase the valve size?

[Mercracer]

Okay. So, I'll plan for GT-40s. Do I port them? Do I increase the valve size?

You are going to be running low RPM's. Unless you are willing to pay a competent shop $1500+ to massage and flow your heads, leave the ports and valve size alone.

[Freshmeat]

The local machine shop wants $500 for port/polish and larger valves. This is all they do- head and engine assemblies.
Are you saying to skip that? I guess I should wait until I select a cam before I get too far into what I'm doing with the heads. It's likely the torque cam would reach its limit before those GT-40s became a restriction, now that I think about it.

[DuceAnAHalf]

We have a set of E8JE heads that came with those valves stock. we believe the exhaust valve is swirl polished stainless.

Do those heads have 2 vertical bars cast on the ends? I thought it started in 89, but those E8JE Marine heads may be the first version of the Modern GT-40 heads used by Ford.

I looked today and there are two bold vertical stripes on the end of the head. :slug:

[Freshmeat]

What do you think about manifolds? I'm all about Edelbrock, but I don't see one designed for low end on the site...

[DuceAnAHalf]

What do you think about manifolds? I'm all about Edelbrock, but I don't see one designed for low end on the site...

the Performer manifold is idle-5,500RPM stay away from single-plane manifolds, such as the torkers, victors and the others. Single plane intakes dont build power till around 2,500rpm

[Mercracer]

What do you think about manifolds? I'm all about Edelbrock, but I don't see one designed for low end on the site...

Performer RPM. Stay away from the Performer unless you are putting it in a truck for towing. The Performer RPM will give you room to grow.

[Freshmeat]

Performer RPM. Stay away from the Performer unless you are putting it in a truck for towing. The Performer RPM will give you room to grow.

It's going to be in an old CJ7 with 38" tires (35s to start) and 1-ton axles. Still recommend the RPM? Aiming the power band to be really low, since most of it will be crawling, anyway.

[Mercracer]

It's going to be in an old CJ7 with 38" tires (35s to start) and 1-ton axles. Still recommend the RPM? Aiming the power band to be really low, since most of it will be crawling, anyway.

For crawling, the Performer would probably be fine.