I have a '78 460 motor I want to put into my '71 4x4. I am not an engine builder, so I am trying to learn as much as I can. I will have someone do the build up for me, but I want to go in with a set of ideas or a plan. I am starting a restofication of the '71 and these are my goals, engine wise, in order of importance:

1) Must run on 87 oct. pump gas (hopefully this is possible, but 89 would be ok if the other goals could not be met)
2) Must have smooth idling cam.
3) Must have better high end power than stock. I am pretty happy with the low end torque, and so any mods must not sacrifice the low end, but can improve it.
4) Gas mileage penalty must be minor (if at all).
I hope this is a realistic set of goals, maybe some one can set me straight.

The primary use of the vehicle will be a runner, but I would like some better street performance when called upon. It will occasionally be used for towing my Jeep as well.

I have searched this forum and others, and this is what I (think I) know:

1) I understand the 460 to have poor exhaust breating characteristics.
2) There are some oiling issues (volume, not pressure).
3) The timining in '78 is retarded for emissions.
4) the conn. rods, crankshaft (and ofcourse block) are good for up to 600hp, so I will re-use them. They will be balanced.
5) To be able to use 87 octane, it looks like the max compression ratio I can use is around 8.7:1
Please correct me on any of these assumptions if I am wrong.

I was thinking of using Edelbrocks alum. heads and intake and adding Thorley headers to help the exhaust breath better. I am also considering Flowmaster with cross over pipes (I have them on my Jeep and am very happy with them). Internally I was considering a Comp Cam, but I am not sure which one. I think I have it narrowed down to one of 3. Either their High Energy 34-225-4, their Xtreme 4x4 34-231-4 or their Xtreme Energy 34-234-4. Again smooth idle is important. A pre-'72 timing gear assy will be used to achieve "straight up" timing. I have no idea on the lifters, pistons (can I run flat tops and meet my goals?) or carb size.

Can anyone tell me if I'm on the right path (go easy... I'm learning ) and provide some direction on the cam, pistons and and carb? I am hoping to bump over the 300hp threshold on this underachieving beast. Thanks!

 

40 views and no opinions?!?!

 

41st view here ---

Howdy Comet --- when speaking of realistic gas mileage on a 460 that is only with the wind behind you.

My "mildly built" 460 (driven daily, so I couldn't go hog wild...) gets about 9.5 - 10.5 mpg; I drive 110 miles daily just for work.

It is an '83 model engine and the timing has been set straight up, so it thinks it's an earlier model engine. Wild lunati cam so the engine can "sing" at red lights, L&L headers, performer intake and avenger 770 dumping into 3" pipes exiting out the rear bumper.
The block has been blueprinted and decked and all the rotating parts balanced and straightened, then a .040 bore added. The heads have been milled.

I am a GM engine mechanic and have to be honest with you when I say this monster screams.... I love the look on the people's faces when they start to DISSAPEAR in my rear view mirror when they've been blown away by a '74 F-100!!

In closing - be careful; the rear tires can/will break loose at a moments notice - great for impressing the babes, but not your checkbook...

 

Thanks Loveoldtrux, great info. Since this won't be a commuter, I can deal with gas mileage in the 10-12 range. What octane fuel do you burn in her? I do want a smooth idle, though. I really like the look of the exhaust exiting out the rear like you did. I have been thinking about that as well. I have been toying with the idea of a Detroit locker in the rear to help it hook up a bit better and also improve it's 4 wheel drive capability.

 

With aluminum heads you should be able to go up to at least 9.0:1 on 87. Compression alone is "only" worth about 3% overall power per point increase. I wouldn't worry about trying to push the envelope on compression. The heads will definitely be a step up over stock. I'm running the 265H Xtreme 4X4 cam from Comp with specs 218/226 @ 0.050 and .514/.524 lift. It idles pretty smooth and has tons of torque and higher end hp. You might want to use their cam that is one notch smaller. That should give you a pretty much stock idle with tons of torque. You'll wnat a shorter cam with that lower compression, so as not to bleed off too much cylinder pressure at lower engine speeds. Personally, I'd go with the Stealth intake. It's better than the PErformer RPM in both hp and torque. As for pistons, it might be possible to run flattops if you buy the large CC E-bocks. You'll just have to check what the compression ratio of the pistons is supposed to be for a given CC size and then adjust your calculation as indicated based on the amount you deck the block, size of gasket, how much you bore, etc. Hope this helps.

 

Bigsnag, yes that is very helpful. I thought I might be able to squeeze a bit more CR out of those heads, but was being conservative I guess. I'll look into that intake you mention-sounds interesting. I understand the Eddy has had sealing problems anyway. I don't know if they worked it out by now or not, just what I've heard.
Also, thanks for the feedback on the cam you have. I assume you typoed the 265H and meant 262H since your specs match the 262H. The next one down is the 256H, which is one I am considering, so another vote for that cam.

 

Yeah, you are right about the cam. I am running the 262. I was going from memory and just mistyped. I did, however, just find out that E-bock is now offering an airgap version of the Performer RPM in both regular and CJ/SCJ port size. That may be the best intake out there. I have nothing to back up that statement except that the airgaps in Windsor motors always outperform non airgaps pretty easily.

 

Yeah, you heard right about the air gap intake. From their website:
Performer Air-Gap® & RPM Air-Gap® Manifolds
This award-winning design incorporates the same race-winning technology that’s been used on our Victor Series competition intakes for years. The air-gap design features an open air space that separates the runners from the hot engine oil resulting in a cooler, denser charge for more power. RPM Air-Gap manifolds are modeled after Performer RPM intakes for high performance street power from 1500-to-6500 rpm, and the new Performer Air-Gap manifolds are ideal for street performance from idle-to-5500 rpm.

Edit: upon further searching it does not appear this is offered for the 460, but it's a little confusing. I sent an e-mail to them for clarification. I'll let ya know what they say.

 

The Air-Gap is indeed available for the 460. Its listed in JEGs.

 

Yep, like Tmyers said, it's true. Here is the official response from Edelbrock:
Yes the RPM air has a part number 7566, it is not available at this current
time, check back with us at the end of next month.

Hey Tmyers of Everett, you aren't the Tmyers of the PNW are you?

 

Nope thats not me. I don't even know what PNW is.

 

Comet - thanks for the Kudos. He runs well with both octanes - just a "slight" ping with lo-lead; but manageable. This Lunati cam is not smooth....you'd swear the pistons are swapping cylnders (listen to the "harrison speaks" link). Other than that, it's a nice ride. Not very many people around here "know" what a decent cam sounds like --- I think all the hot rodders in Rome have moved out. Nothing but rice-burners and old fuddy-duddies left any more!!...