Replacement 305 for a 1961

[Jmclendon]

Hello all,
If I was on the market for a replacement engine, would y'all happen to know how flexible I can be in terms of the year?

I'm not looking to get rid of what I've already got..... I'm just hoping to kill two birds with one stone. My current engine has a knock until it gets warmed up. So, I'd like to pull it so that I can see what's going on and fix the problem (and hopefully learn along the way). But in the meantime I don't want the old man to sit around doing nothing. So I figure if I can get a decent rebuilt replacement put in, then I get the best of both worlds. But, I want to stick with the 305 V6.

I've got a 305D under the hood at the moment. He's a 1961 1500.

While I'm on the subject, if anyone has a suitable pre-loved engine just lying around. Well now, I might be able to take it off your hands LOL

[TJ's GMC]

That's gonna be some heavy freight there. I'll leave it to the experts that know the exact details, but I THINK any 305A-E should be pretty much a direct replacement.

[David R Leifheit]

Originally Posted by TJ's GMC

That's gonna be some heavy freight there. I'll leave it to the experts that know the exact details, but I THINK any 305A-E should be pretty much a direct replacement.

Correct on both counts.
It -will- be a heavy freight..
and
Any 305A - E will (or should) bolt right up.
So will any 351 v6

[TJ's GMC]

Hey if you're not in a big hurry there is a guy on youtube Rebuilding a 305. It has been bored .060 over to. He's perrty dang smart, and the motor will be for sale when completed. 3 parts so far...stay tuned to see the rest.

Part 1: https://www.youtube.com/watch?v=FXPKRjzxRTo

Part 2: https://www.youtube.com/watch?v=oWesd1oXpFo

Part 3: https://www.youtube.com/watch?v=DtMB13ochL4

[Funky61]

Thanks for those links TJ!

[Jmclendon]

Thanks for the links! Definitely one to watch later tonight.

When y'all say any 305 or 351 would work, does that mean I should be fine with anything from 1960-66? Or is there some practical benefit in trying to stick with one from the same year?

[TJ's GMC]

Originally Posted by Jmclendon

Thanks for the links! Definitely one to watch later tonight.

When y'all say any 305 or 351 would work, does that mean I should be fine with anything from 1960-66? Or is there some practical benefit in trying to stick with one from the same year?

You should be fine with any 305 from 60-74. Personally I'd look for a 67-74 305E as they had a little more power. If I remember right....a whole 10 HP.

[Jmclendon]

Originally Posted by TJ's GMC

You should be fine with any 305 from 60-74. Personally I'd look for a 67-74 305E as they had a little more power. If I remember right....a whole 10 HP.

LOL I'm quite happy not worrying too much about the HP. The truck and I just don't have the souls of a hot-rod I'm afraid.

Thanks for the tip. That expands my options a bit....

Y'all are right about freight being an issue. But, I'm banking on a quality rebuild shipped on a container being cheaper (and less of a hassle) overall. Maybe... Hopefully.

[bobdylan]

I would think that a knock that went away after it warmed up, could not be to serious. If it was a rod bearing I think it would get worse. How is your oil pressure? You will see a drop in pressure if you have a bad bearing. Have you checked compression? I would not pull to investigate until I knew what was going on.

[David R Leifheit]

Originally Posted by Jmclendon

LOL I'm quite happy not worrying too much about the HP. The truck and I just don't have the souls of a hot-rod I'm afraid.

Thanks for the tip. That expands my options a bit....

Y'all are right about freight being an issue. But, I'm banking on a quality rebuild shipped on a container being cheaper (and less of a hassle) overall. Maybe... Hopefully.

You are talking an engine that has been known to kill an engine stand or two.

I'd say estimate 1000 pounds for engine and crate.
Weight of the engine/motor alone, according to Jolly's data:
305A = 738 lbs.
305B = 771 lbs.
305C = 840 lbs.
305E = 795 lbs.
351 = 860 lbs.
401 = 880 lbs.
478 = 925 lbs.
702 = 1485 lbs.
637 = 1219 lbs.
Then add crating.

As pointed out, 1960-1974 305 & 351
But also since you already have one in your vehicle, and thus the physical mounts aren't a concern (the metal mountings, not the rubber part although those are always a concern) you can also look for one out of any truck size. The 305 was available up through at least the 5500 series, and as far as I know the same holds true for the 351s as well. The mounting in the bigger trucks is typically at the front of the engine and the mounts on the bell housing, as opposed to the pickups where the mounts are on the sides of the engine and the bell housing.