1964 GMC truck 401 magnum V-6

first mud bog with stock 40 y.o. 401 magnum with zoomies and holley 4064 500 cfm carb and no govenor

Category:

Autos & Vehicles

Tags:

• GMC
• truck
• motor
• sport
• mud
• bog
• 401
• magnum
• v-6

[yee11111]

hey man these engines are cool i might be getting a 478 magnum what kind of rpm can these engines handle you think about a biger cam and working with heads a little bit will get em to turn more rpm

[hunternaf]

One member of the yahoo 6066_GMC club says 5,000 rpm from a 401 M for short periods, I have seen my tack close to that and I have 0.030 milled from the heads for the fall run but it lost rpms just like in this video so I am going to run an electric fuel pump in the spring. There are no performance parts available but there are club members that have had cams reground and aftermarket pistons manufactured. The group has 5-600 members all V-6 enthusiest thats where you need to go for info

[noshsreqd]

Sounds great with the zoomies, you can hardly tell it's a V-6! I'm running a 401 I built up in my '67 CM-2500. I would say try feeding yours some nitrous for what you are doing before getting into any expensive mods.

[hunternaf]

thanks I think my next mod will be better tires after I get the new heads on, can you say rockwell axles

[hunternaf]

hope you are hooked up with the 6066_GMC group on yahoo or at least the 6066 gmc page, 305's are all right and I still own one but 351 is better and 401 the best bolt in swap allong with the holey grail being the magnum in 401 Good luck and let me know if you need something Gary

[subbass32]

Y'all might be a redneck if....LOL!! Man that sounded good!! Keep up the good work and you'll make it, but it'll sound awesome even if you dont!!!

[hunternaf]

labor day bog it will get the new heads milled .030 and fresh valve job

[madjimms]

Sounds like a retarded ratchet.

[Alisterwolf66]

I wouldn't try it - 478Ms are rare, for a start! They normally ran in the mid-2000rpm range.

I'll put it another way: the crank weighs well over 110lbs. Each piston and rod assembly weighs about 8lbs. Couple that with an 80lb flywheel... and you get the message. That's a LOT of rotating weight being asked to spin twice the revs it was meant to!

[yee11111]

what about the 478 magnum will it be able to turn 5,000 rpm or will it not last

[gnarkill445]

that 6066 home page has alot of useful info i love that site so much