decode my v6

[oldno7]

http://67-72chevytrucks.com/vboard/a...01&d=136676788

So im thinking about these motors I found and thought they would be good for my c-30 project. There is 2 v-6 gmc motors that this older fella has One is to be a 401 magnum and the other is a 305. Here are a few pics I took of one of the motors and these are some numbers i got i think these were on the exhaust manifold and was wondering if you guys could help me figure this out or will i just need to go back and get info of front of motor.

[GVDobler]

Go over to Jolly's website. Good guy and tons of info on that engine.

http://www.6066gmcguy.org/

[MusicMan70]

The 401M is preferred; both being in equal condition. Check on the front

[Corts60]

That number on the exhaust manifold is a part number. I agree with above that the 401 is more desirable but also harder to find parts for (internally). Whatever you do, keep the top end off of that 401. Those are magnum heads with larger ports/valves and the intake is specific to those heads as well as the exhaust manifolds. That top end will bolt to a 305.

[oldno7]

I will be going back over to this fells house this weekend and will get more info on the motors. I'm not sure what he would want for them. Would 500 be to much to give for them. I'm a little pumped up about getting them

[Corts60]

When is the last time they ran? Have they been stored inside? Lots of variables to consider. If he wants $500 for both, go for it.
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[slorio]

OldNo7:
Does he have the bell housings with them as well? Your C-30 Chevy bell housing won't bolt up to those GMC's. They have a GMC bell housing on EBay for sale now, if you need one.
Regards,
Steve
New Orleans

[oldno7]

I'm not really for sure, I want to say one of the motors did are they the same bell housing for all the gmc v-6. In other words will a bell housing of a 305 work for a 401 or vs versa. I will no alot more this weekend. You don't happen to have that link do you for ebay. I will try looking.

[slorio]

Old No7 :
Yes the bolt pattern on the 401 is the same as the 305, so any of the V6 bellhousings will bolt to the other V6's. Only thing to look for on the bellhousing is if it is for the small trucks or the big trucks. Depends on what the engines came out of but the big truck bell housing won't fit in a pick up. Here's what the small truck bellhousing should look like:

http://www.ebay.com/itm/1966-1967-19...r#ht_641wt_674

If you are interested in these motors, a wealth of knowledge resides over here:

http://6066gmcclub.com/forum/index.php

Hope this is helpful.
regards,
Steve
New Orleans

[oldno7]

So I for sure have to have the small bell housing, I'm sure these motors came from big trucks should i get the one of ebay i think its a small bell housing i need to look again thanks for your help this is all new to me and i feel like im being rushed

[oldno7]

Also is there anything else i should inquire about is this housing the only thing im going to need to run this 401 Just want to make sure i get what im gonna need

[slorio]

OldNo7:
Does he have the motor mounts and the stands that bolt to the frame? Those will be different than your chevy. The motor mounts are getting hard to find although some substitutes are available. If the engines came out of big trucks, I would see what flywheel and clutch they have. My pickup uses an 11" clutch. Those may use much bigger. The flywheel for the 305 and 401 should interchange. Both are internally balanced. The 478 and 379's are externally balanced so they would not interchange with 305/351/401.

Hope this helps.
Regards,
Steve

[oldno7]

So i stopped by Earls place this morning to pick up my c-30 i bought from him, I didn't have much time to browse around cause i wanted to get back to the house before it started pouring, but i did glance at the v-6s again this is for sure a 401m and the other one he has is a 478m I never did ask him what i could pick them up for i might just let these sit where they are for awhile im torn what to do the c-30 i just got has a 292 with the sm420 trans and dont no if i should keep that set up or go for the 401m route either would be cool. Since this other motor is a magnum (478) can the heads be used on the 305 for better performance i no guys use the 401 heads and that on the 305 for better performance but wasnt for sure you could use the 478 stuff

[MusicMan70]

If your going to go this route(GMC V-6), I'd get the 401M or 478m and forget about swapping heads onto a 305. I believe the heads are the same on the 401M and 478M. Just pick up the extra cubic inches.

[MusicMan70]

Here is another Erl with some GMC V-6 info and awesome truck!

http://67-72chevytrucks.com/vboard/s...d.php?t=306611