Frame off Restoration 73K5 - Where to find 350 heads/carb/mainfold

[75K5]

Working on a frame-off for a 73 K5 Blazer. It came with the original block, but the previous owner upgraded the heads, intake, cam, and carb. I want to bring this back to 100% stock. Can anyone help with which heads, cam, intake manifold, and carb I need to locate? and any good ideas on where to get it?

This blazer has 39,000 original miles. Can't wait to get it running.

 

[fastazz81]

What engine?

 

[75K5]

It's a 350, assuming 4Bbl

 

[RubberFloorMat]

why not just paint it all to look stock and save yourself a ton of money and keep the performance boost. Its not like its going to Monterey for a concourse judging. maybe slip a less aggressive cam in so its not really obvious if thats your thing.

 

[76k5blazerr]

why not just paint it all to look stock and save yourself a ton of money and keep the performance boost. Its not like its going to Monterey for a concourse judging. maybe slip a less aggressive cam in so its not really obvious if thats your thing.

I have a good stock cam that I just pulled out of my 72 350. Also have the heads, intake and q jet carb. Motor ran great but I upgraded to aluminum heads and intake. I would sell the stuff pretty cheap. PM me if you want any of it.

 

[RubberFloorMat]

I've got a gm crate motor but thanks for the offer.

May I ask why other than wanting a stock appearance?

 

[75K5]

Trying to do a number match build 100% stock!

 

[75K5]

I sent you a PM 76k5blazer, I am interested in stock parts.

 

[1975Jimmy]

You'll need to find a set of 882 heads with the right date code. Not terribly difficult. Pretty much any 73 GM car or truck used those heads. But, fair warning, they are low compression heads, and you won't make a whole ton of power with them especially with the stock cam. Even if the engine is completely dialed in, rings are in good condition and everything is within spec, the engine really will only make about 150 to 165 hp. Also, if you're going numbers matching, remember HEI ignitions came out in 74, so you'd also have to run an old school points setup.

For what it's worth, sometimes the trouble of doing a numbers matching restoration doesn't pay off. If you're doing this thinking that it will make the rig worth more in the end, don't hold your breath. Things like an upgraded cam, intake manifold, better flowing heads, and HEI ignition all breathe new life into the motor and will add to the overall enjoyment of the truck and likely make it more valuable down the road.

 

[1975Jimmy]

why not just paint it all to look stock and save yourself a ton of money and keep the performance boost. Its not like its going to Monterey for a concourse judging. maybe slip a less aggressive cam in so its not really obvious if thats your thing.

Agreed! I'd sing a different tune if this was a Nomad or GTO Judge, but it's not and the stock engines in our trucks were dog slow.

 

[75K5]

Not bad suggestions and great information. I could use the stock block which is a numbers match, and may run a stock cam, stock intake, stock carb. But leave the 383 bottom end and aluminum heads. I want it to have stock drivability characteristics. A little extra cubes and head flow is probably not going to change that much.

 

[1975Jimmy]

Not bad suggestions and great information. I could use the stock block which is a numbers match, and may run a stock cam, stock intake, stock carb. But leave the 383 bottom end and aluminum heads. I want it to have stock drivability characteristics. A little extra cubes and head flow is probably not going to change that much.

If you leave the 383 bottom end, have higher compression aluminum heads with larger than stock valves, the duration on a stock low compression 350 cam is not going to allow that motor to perform very well.

If you don't mind me asking, what is the appeal of lowering the horsepower and detuning the engine? If it's a good runner, I'd keep it that way. The only reason I'm curious is because my 75 was bone stock original when I first got it and even with 3.73 gearing it needed a sundial to clock its 0-60 time. Since swapping, cam, intake and rebuilding the heads, it's now able to keep up with traffic. It's no rocket, but I felt that the stock 350 was so low on power that it made it sort of unsafe to drive in modern traffic.

 

[75K5]

I have a fast 75K5, it's got a 5.3L and 4L80. I want one that's authentic and original, or as much so as possible. It's not a daily driver since it's going to be a complete frame-off

 

[1975Jimmy]

I have a fast 75K5, it's got a 5.3L and 4L80. I want one that's authentic and original, or as much so as possible. It's not a daily driver since it's going to be a complete frame-off

Gotcha! Makes sense. Well, luckily sourcing the parts will be fairly easy. 882 heads, iron intakes and stock cams are a dime a dozen at junk yards. Also, a rebuilt 4MC Quadrajet carb can be had at nearly all parts stores. That should get you where you want to be.

What kind of aluminum heads are you running currently and are you interested in selling them?

 

[75K5]

I'll get it all pulled apart and let you know what they are. He claims it's a 500HP motor, but doesn't every seller say that!!

 

[75K5]

OK, I'm going to keep the stock block, but leave the stroker crank and pistons. Looking for a set of 882 date coded heads, shouldn't be too tough.
Any ideas what the part number for the carb should be? I think I have an intake and cam lined up.

 

[1975Jimmy]

All our trucks rocked some variant of Rochester's quadrajet, the best carburetor money can buy IMO. Your truck would have come from the factory with a 4MV with divorced choke unit on the intake manifold and 1-inch threaded fuel filter housing/fuel inlet. If you're using a factory intake manifold from a year correct vehicle, it should have the right provisions for that style of choke. You can also find aftermarket intake manifolds that will accept that style of choke. I have an Edelbrock Performer intake manifold that works with my 4MV's divorced choke unit.

The carburetor you need looks like this.

Some people swap these out for electric choke 4ME units as they "can be" less difficult to setup. That said, once you get over the fear of bending the linkages, properly setting the choke on a 4MV is easy.