Can someone tell me engine harness differences?

[ts71281]

Ok, my truck was originally a 307 3 speed manual truck but has since been converted to a 454 with a 4 speed muncie. It's time to replace the engine harness since it's in really rough shape. What's the difference between a smallblock v8 engine harness and a big block v8 engine harness? I am going to order one or the other but even the customer support lines at AAW or MH electrical cannot tell me the difference. Also, is it worth the 8 week backorder from MH or just order immediatly from AAW? Thanks in advance guys.

[ts71281]

Anyone? I'm wanting to order something tomorrow!

[ts71281]

Still nothing?

[raycow]

I don't know the difference, but I can think of a few questions that you would need to answer before you decide.

Did any wires on the 307 harness NOT reach their connection points on the 454 without requiring extensions to be spliced on? Which side is your alternator on? Is your oil pressure switch near the distributor or the oil filter?

Did you have working reverse lights with the 3 speed? Actually, this might not be an engine harness issue, but the switch will be in a different location.

Do you have any reason to believe the MH product would be preferable in some way to the one from AAW?

Ray

[ts71281]

raycow, the 307 harness worked fine but was a wee tight from the coil to the starter. I don't know if it's from the wire being broken over the years or what.

Alternator is on the drivers side

there's no oil pressure switch, just a hard line that runs to the mechanical guage

last but not least the crabby lady at aaw didn't impress me. She had no technical knowhow and didn't want to look up the schematics for me to tell me the differences between the two.

The guy at MH was super nice, gave me a 10% discount, still didn't know the difference but was willing to take the big block harness back if it didn't work. Last but not least, the MH one comes with a new gutter, the lady at AAW says crabbingly, "just the wires only sir!"

[raycow]

Your alternator is on the same side as stock, so that shouldn't be an issue.

Going from your experience on the phone, I would say to order the BB harness and to order it from MH. The wait will be worthwhile. It's the people that make the difference in the long run.

Ray

[ts71281]

I got it from MH and it's going to ship next week. I couldn't be happier with the service and their patience

[FRENCHBLUE72]

M and h rocks I like them better than paintless for stock applications..

[GASoline71]

I have 2 harnesses from M&H in my 1972 GMC truck... the engine harness, and the front light harness. Couldn't be happier with their quality and how they match up perfectly with the stock harnesses. All the mounting points and wire wrap are exactly what the stock harnesses have.

Gary