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1977 460 Update/Upgrade

3K views 3 replies 2 participants last post by  Ozzie H. 
#1 ·
I recently purchased a 1977 Ford Diamond Mini-motor home with intentions of refurbishing it and hitting the road. The running gear is basically a stock Ford E350 Econoline. It has 26,000 original miles. The unit weighs around 9000 lbs, loaded. Some preliminary research tells me that the transmission is a C6. The 460 does not appear to have any modifications. Any engine upgrades that I will do will be based around gas mileage and reliability. A performance increase would be nice, too. My planned engine budget is $2000.

All work that I do will have to be done with the engine in the vehicle, since I don't have the equipment or facility to pull it.

Within my budget, what modifications make the most sense for this project based on best possible gas mileage and reliability?

Thanks.
 
#2 ·
I recently purchased a 1977 Ford Diamond Mini-motor home with intentions of refurbishing it and hitting the road. The running gear is basically a stock Ford E350 Econoline. It has 26,000 original miles. The unit weighs around 9000 lbs, loaded. Some preliminary research tells me that the transmission is a C6. The 460 does not appear to have any modifications. Any engine upgrades that I will do will be based around gas mileage and reliability. A performance increase would be nice, too. My planned engine budget is $2000.

All work that I do will have to be done with the engine in the vehicle, since I don't have the equipment or facility to pull it.

Within my budget, what modifications make the most sense for this project based on best possible gas mileage and reliability?

Since it only has 26,000 miles on it, all should be good with the engine unless something foolish was done to it. You could do a compression check to verify.

Be sure that you have adequate cooling for the transmission's fluid. Add more if it's insufficient.

If it still has the factory's cam gear in it change it to an all metal gear. That also would be a good time to reset the cam timing to pre-smog.

Many RV owners have realized performance and fuel economy by improving exhaust and cold air intakes. Here's one source: Banks Power | Diesel Performance and Gas Performance Products

Your ignition will likely be a Duraspark II. If you want more spark switch to a Duraspark I or make your own HEI using a GM module and coil. Relocate the module to a cool location and always carry a spare for any semiconductor controlled ignition.

If it has old tires on it (over 7 years) replace them with new radials. That will likely have a great impact on your budget. Always keep them inflated properly.

Try to get it to run as cool as possible. Heat has ruined many engines and transmissions in RVs.

Be aware of the emission testing requirements for the area where the vehicle will be registered. Some smog equipment may be able to be modified to get better fuel economy but if it can't satisfy the law it's not worth it.

RVs are not famous for great fuel economy. Drive in a conservative manner.

Check the brakes thoroughly. Brakes that drag will kill performance and fuel economy.

Always keep everything in a good state of tune and maintain fluids and filters properly.

Use engine oil with sufficient zinc compounds added and viscosity for your environment. This will discourage wear & cam failure.

Grease the chassis regularly including the U-joints. If it's got a two piece driveshaft check the center support.

Get a set of Ford truck shop manuals for the chassis you have. Read it, understand it, and follow it. Originals or CD reproductions should work.

Be sure that either the carburetor's automatic choke works correctly, or switch to a manual choke & throttle set up. It should close on a cold start and open completely after warm up.

Don't run on any higher octane fuel than is needed to get the engine to run properly without knocking.
 
#3 ·
Thanks Ozzie !!

Thanks for the input, Ozzie !

I've done a lot of reading on this forum and it has given me quite a few good ideas for improving this engine. But there are so many I really don't know where to start. Improving on the Duraspark 2 was one of the first things I read. Another was changing the timing gears/chain to a 1968-71 set to undo/reset the smog timing, as you suggested. Someone suggested either doing the work myself or buying a correctly curved Duraspark 2 distributor. Question there is since both involve changing factory timing do I recurve the distributor AND change the timing set...or is this redundant ?? I guess it wouldn't be since one is ignition timing and one is cam timing...right ??

I think headers and dual exhaust are a no-brainer. Hedman long tubes seem to be the popular choice there. My question on this issue is X-pipe or H-pipe and what mufflers (Flowmaster 50's ??)

I haven't decided if a better intake and carb will give me a mileage/reliability/performance gain to make it worth it. A lot of suggestions to go with a Edelbrock Performer (not the RPM model) and an Edelbrock 750cfm with electric choke might give me what I'm looking for.

And my last option is a cam but I didn't want to get that deep into the engine unless someone thinks it would be the best idea ever !!!

And yes. I WILL be doing a compression test to make sure this is all worth the time and money.
 
#4 ·
Thanks for the input, Ozzie !

I've done a lot of reading on this forum and it has given me quite a few good ideas for improving this engine. But there are so many I really don't know where to start. Improving on the Duraspark 2 was one of the first things I read. Another was changing the timing gears/chain to a 1968-71 set to undo/reset the smog timing, as you suggested. Someone suggested either doing the work myself or buying a correctly curved Duraspark 2 distributor. Question there is since both involve changing factory timing do I recurve the distributor AND change the timing set...or is this redundant ?? I guess it wouldn't be since one is ignition timing and one is cam timing...right ??

The part about the timing gears/chain is for two reasons. First the chain will slacken with use. The other factor is that Ford (& other manufacturers) used on the cam an aluminum gear with nylon teeth. It can fail with little or no warning stranding you somewhere where you'd probably not prefer to be stranded and depositing most of the nylon pieces in your oil pan and your oil pump's pickup screen. Cam timing and ignition timing are two separate matters. Either or both would likely benefit you. There are several approaches to re-curve. Here is one: Duraspark_distributor_recurve_instructions_index

I think headers and dual exhaust are a no-brainer. Hedman long tubes seem to be the popular choice there. My question on this issue is X-pipe or H-pipe and what mufflers (Flowmaster 50's ??)

Naturally the least restrictive exhaust is preferred in general, but it can also become too noisy in some cases. I'll let someone else recommend mufflers as I don't consider myself an expert there.

I haven't decided if a better intake and carb will give me a mileage/reliability/performance gain to make it worth it. A lot of suggestions to go with a Edelbrock Performer (not the RPM model) and an Edelbrock 750cfm with electric choke might give me what I'm looking for.

There may not be enough change to justify the cost. If you have the Motorcraft 4350 it can be made to perform reasonably well when it is "right". Whichever carburetor you end up with be sure that it is adjusted properly and be sure the choke is working correctly. A choke which doesn't work correctly will make starting more difficult and will damage performance & economy. I had so much difficulty with mine that I switched to a manual.

And my last option is a cam but I didn't want to get that deep into the engine unless someone thinks it would be the best idea ever !!!

My guess is that a cam change also wouldn't be justified if you are working on a budget.

And yes. I WILL be doing a compression test to make sure this is all worth the time and money.
Ozzie
 
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