How do I shop for the motor that is not original

[cowlby]

I have a 72gmc 1500 sierra that has a rebuilt 350 out of 78 blazer.

Engine details I know:

A 350 out of a 78 blazer is what I was told.
He added an HEI ignition, RV cam , A carter AFB, a holley performance intake, and later I added some headers to his rebuild.

I want to replace the spark plugs and ignition wires and possibly the hei distributor and coil cap.

My Question: When shopping for these items do I specify my vehicle as the 78 blazer (and guess at the model some sites ask for) or a 72 gmc sierra?

Thanks for any shared knowledge.

[Wrenchbender Ret]

A lot would depend on how much of the old engine was used on the replacement. It sounds like the HEI came with the replacement engine. When ordering parts relative to the engine just order for the 78 Blazer. Everything except the dist parts will be the same.
George

[rpmerf]

Look for parts for the 78 blazer, since that is the engine they are going on. Some thoughts and things to be aware of.

Plugs - You could pull what is in there now and grab a part number. Main concerns are flat seat or taper seat, and how long the spark plug is from the seat to the tip.

Wires - Be aware of how the end connects to the distributor cap. How you route the wires will determine how long they need to be, but if you grab a factory set, they should fit the factory way. Some aftermarket sets specify 'over valve cover', or 'under exhaust'. Since you have headers, you may want to consider aftermarket wires that are heat resistant.

Don't know that I would replace the whole distributor, maybe just the module inside.

Coil cap - search for the 78 blazer, or just for GM factory HEI.

rockauto.com is good for factory replacement parts. Lots of options, with pictures and fitment guides to help find the right part and compare against different vehicles.

summitracing.com and jegs.com are good for aftermarket parts.

[special-K]

Go by the engine. You should be good with the general info you have for the parts you ask about. But if you want to know exactly what the engine is from you can get the stamped suffix code off the block pad just in front of the head on driver side and look it up. For plug wires on my '72 with 350 and headers I ask for '75 Corvette wires because those were run out the top, same as I do, and the Vette had HEI

[Minkota]

Originally Posted by cowlby

My Question: When shopping for these items do I specify my vehicle as the 78 blazer (and guess at the model some sites ask for) or a 72 gmc sierra?.

I would not take the previous owners word for it, he may be telling you what he was told. Bring the parts you want to replace in with you.

I had this very same thing happen on my previous truck, the person I purchased it from claimed it was the engine out of a 69 suburban and it turned out to be out of an 85 camaro.

Even if the engine is from the 78 Blazer there is way to know if the heads came from the same vehicle without doing some more investigating.

[GASoline71]

There were no HEI ignitions in 1972 so go with the 1978 for the HEI and plug wires.

Gary

[GWWhite]

I had to start getting part numbers, the item and pictures and went to the dealer parts guy. Be surprised what the oldest guy knows. OBTW when you find him keep in touch!

[cowlby]

Thank you guys for sharing your opinions/suggestions.

I will get the numbers off the block and heads and determine for sure what I have and then buy for that. I took notice of the other points about the wires and HEI etc. Good stuff.

Lee

Lee

[HIGHWAY BY THE SEA]

Yes, go by the engine application. I have a mid 1970s 350 engine in my 67 GMC 3500, and it always works for me. I also take a picture of the engine when I go to parts stores to help with the parts questions.