New guy on the block

[73C30crewcab]

Hello all!

Purchased a 1973 C30 3+3 454 from a hack lawyer whose kid didn't appreciate it. Long story short, after owning for nearly 3 years and investing much blood, sweat, and tears, I'd like to make this ongoing project my daily driver.

The build:
1973 crewcab 1 ton 2wd Cheyenne, originally light green but was later "painted" by what seems to be an Earl Scheib paint job from 20+ years ago. Truck was assembled in January of 1973, built in Maryland and sent to California until the late 1980's, been in TX ever since. Upon purchase, truck needed literally everything and I've slowly been building back to as stock condition.

Direction I'd like to take:
Currently building a 454 in near stock form as I have no plans for this other than drive it daily. Also going to install A/C as the truck is an A/C delete model. Plan of rebuilding TH-400 and adding overdrive.

Question for now:
First, (please laugh as I know this is a ridiculous question), what tips does anyone for increase fuel economy? I know, I said it. Upon reading some of the near endless forum pages, up to 15ish mpg on highway CAN be achieved. I am a open book and welcome constructive feedback but, I have been in the car/truck hobby for 15 years, not a newby, just hoping for a little guidance.

Thank you all for the time and I am happy to be a member.

 

[Charlie]

 

[1987 GMC Jimmy]

Welcome! Show us what you have when you get a chance. It’s good to have the economy conversation while the motor’s on the bench. I’d say don’t go nuts on the cam. Something that would be described as an “RV cam” would probably be best for low end grunt, keeping your net vacuum steady and high, and making the best use of what the engine takes in. You don’t want the BBC equivalent of a peanut cam, and you don’t want to go crazy either because you’ll want to have your HVAC controls and cruise control, if you have it, working properly. Someone can direct you on heads, but I’m thinking peanut ports would be the better choice for economy.

Go aftermarket aluminum intake for a slight performance increase and a less frustrating engine assembly.

If it has a Quadrajet, keep it. If not, get one. Or if you want to be fancy, do an aftermarket EFI, FiTech for example. The latter will probably be about triple to quadruple the price depending on whether or not you have a Quadrajet at your disposal and sending it to get rebuilt and upgraded.

Convert from points to HEI if you haven’t already. The only two advantages to points are the adjustability factor (HEI either works or it doesn’t) and points are more likely to survive an EMP attack.

Headers will help the engine exhale better, which is a plus. If there are any emissions things to delete, get rid of them (i.e. catalytic converter).

Are you doing a gear vendor for the overdrive? Have you considered swapping to a 4L80E and controller? I would think that’s slightly more feasible unless you can pull a vendor out of motorhome. Gearing is another thing, which I guess that wouldn’t be a big deal if you had six forward gears. If you went the 4L80E route a slightly lower ratio would help with the highway RPMs, which is valuable if you don’t do much city driving.

 

[WFO]

Welcome from up in the Panhandle.

 

[73C30crewcab]

Hello Jesse!

I will post pics as soon as I am able. Agreed, figured now was the time to do so. Agreed, I actually have a Lunati hydraulic flat tappet on hand. Specs for cam are 217 duration at .050, .517 lift, and on a 112 lobe seperation.
No HVAC and no cruise, very basic first year truck. Good to know on the heads. I have the factory large oval port castings and would prefer to rebuild and reuse them but will do my homework on the peanut ports.

Agreed on intake, the factory cast iron unit is an 80lbs boat anchor, must be the worst flowing head GM made.

Has factory (amazingly, ran the numbers) Quadrajet and will be rebuilt. Have looked into the aftermarket EFI but budget doesn't allow right now.

Have an MSD HEI Kit ready for it.

Have hooker headers for it. No emissions on truck any longer. Pre catalytic converter which is a plus.

This is the $$$ part for me. The gear vendors are pricey, the 4L80E and controller kit isn't that much cheaper, and I only recently discovered the vendors in motor homes and am going to look into that option.
Truck has factory 14 bolt with 3.73 gears. This is primarily going to be a highway cruiser and long distance driver for my family and I.

 

[1987 GMC Jimmy]

That’s a good all around gear ratio. I wouldn’t change anything with that. Did you have another plan to get overdrive, or were you just articulating that money is the issue regardless of the route? Make sure you have good plugs and wires and correct gap spec for HEI. It doesn’t need to be as close since the spark is so much better. Not 100% on the oval vs. peanut debacle, but there are plenty of guys here who live and breathe big block. Sounds like besides the transmission dilemma, everything will sort itself out naturally.

 

[Rusty Nail]

 

[Crispy]

Welcome aboard. Sounds like you have some parts in the chamber for the 454 build. Personally I dont see 15mpg with a 454 TH400 and 3:73's happening unless you are running a highway tire, on flat road or downhill, and possibly behind a tractor trailer. I'm sure you dont want to hear it, and it may not be the popular opinion but I would set out looking for a 6.0 / 4L80E combo from a 3/4 ton truck or van. Power, economy, reliability, etc. The swap has been done to death and while it isnt a full bolt up affair theres a lot of support for it and it can be done in your yard or garage.

 

[dvdswan]

Welcome to the site.

 

[Craig 85]

FYI, peanut port heads are not compatible with an Edelbrock Performer intakes if you chose to go that route. I had an '80 3+3 with a 454 and 4.10's. I probably never saw more than 10-11 MPG.

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[animal]

 

[donnieray]

Welcome! I love those crew cabs.

 

[73C30crewcab]

That’s a good all around gear ratio. I wouldn’t change anything with that. Did you have another plan to get overdrive, or were you just articulating that money is the issue regardless of the route? Make sure you have good plugs and wires and correct gap spec for HEI. It doesn’t need to be as close since the spark is so much better. Not 100% on the oval vs. peanut debacle, but there are plenty of guys here who live and breathe big block. Sounds like besides the transmission dilemma, everything will sort itself out naturally.

Leaving rear end alone save for an eventual rebuild. Money is somewhat the issue especially if i wanted to do this in a timely manner. I am however patient and only want to do this once. Thank you for the tip on the plugs, HEI's are new for me as I've dealt with points and Mallory Unilite kits mostly. I'm of the live and breathe big block variety and out of personal preference, like the larger oval port heads. Agreed, will chime in once I've made a decision. Thank you again for your time and input.

 

[1987 GMC Jimmy]

You’re welcome! Feel free to start a build thread to track your progress. People will pop by and see what you’re doing, and best of all it documents your project and helps keep you on track.

 

[1973c10]

Welcome aboard