Anatomy of a dinosaur... Inside a gmc v6

mine is a np 540, has a .82 fifth gear
I have seen a few of the 1:1 fifth gear 5 speeds as well.

if you are lucky here should be a metal data plate inside the glovebox door that has the transmission model.

here is a chart of gmc trans and ratios.

<table frame="box" align="center" bgcolor="#fffff0" border="2" cellpadding="2" cellspacing="2"><tbody><tr><td>

Manufacturer​

</td> <td>

Transmission​

</td> <td>

1st​

</td> <td>

2nd​

</td> <td>

3rd​

</td> <td>

4th​

</td> <td>

5th​

</td> <td>

Rev​

</td> <td>

Oil Capacity​

</td> </tr> <tr> <td>

General Motors/Muncie​

</td> <td>

SM-318​

</td> <td>

2.94:1​

</td> <td>

1.68:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

​

</td> <td>

2.94:1​

</td> <td>

2 pints​

</td> </tr> <tr> <td>

Warner​

</td> <td>

T-89B​

</td> <td>

3.17:1​

</td> <td>

1.75:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

​

</td> <td>

3.76:1​

</td> <td>

2.75 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

746G​

</td> <td>

3.02:1​

</td> <td>

1.76:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

​

</td> <td>

3.95​

</td> <td>

?? pints​

</td> </tr> <tr> <td>

General Motors/Muncie​

</td> <td>

SM-420​

</td> <td>

7.06:1​

</td> <td>

3.58:1​

</td> <td>

1.71:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.78:1​

</td> <td>

6 pints​

</td> </tr> <tr> <td>

General Motors/Muncie​

</td> <td>

SM-465​

</td> <td>

6.54:1​

</td> <td>

3.57:1​

</td> <td>

1.70:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.54:1​

</td> <td>

6 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

435GA​

</td> <td>

4.56:1​

</td> <td>

2.28:1​

</td> <td>

1.31:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

5.64:1​

</td> <td>

6.75 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

435GD​

</td> <td>

4.90:1​

</td> <td>

2.27:1​

</td> <td>

1.19:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

8.26:1​

</td> <td>

6.75 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

435GL​

</td> <td>

6.68:1​

</td> <td>

3.34:1​

</td> <td>

1.66:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

8.26:1​

</td> <td>

6.75 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

433G21​

</td> <td>

6.47:1​

</td> <td>

3.35:1​

</td> <td>

1.86:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.86:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

433G22​

</td> <td>

6.47:1​

</td> <td>

3.35:1​

</td> <td>

1.86:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.86:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

434G22​

</td> <td>

6.68:1​

</td> <td>

3.35:1​

</td> <td>

1.86:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.86:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

540GD​

</td> <td>

6.05:1​

</td> <td>

3.31:1​

</td> <td>

1.84:1​

</td> <td>

1.17:1​

</td> <td>

1.00:1​

</td> <td>

6.86:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

540GL​

</td> <td>

7.41:1​

</td> <td>

4.05:1​

</td> <td>

2.40:1​

</td> <td>

1.48:1​

</td> <td>

1.00:1​

</td> <td>

7.85:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

540GO14​

</td> <td>

6.05:1​

</td> <td>

3.31:1​

</td> <td>

1.84:1​

</td> <td>

1.00:1​

</td> <td>

0.82:1​

</td> <td>

6.86:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

541GD​

</td> <td>

6.15:1​

</td> <td>

3.30:1​

</td> <td>

1.86:1​

</td> <td>

1.17:1​

</td> <td>

1.00:1​

</td> <td>

6.13:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

New Process​

</td> <td>

541GL​

</td> <td>

7.25:1​

</td> <td>

3.88:1​

</td> <td>

2.19:1​

</td> <td>

1.37:1​

</td> <td>

1.00:1​

</td> <td>

7.22:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

261F​

</td> <td>

6.32:1​

</td> <td>

3.41:1​

</td> <td>

1.77:1​

</td> <td>

1.00:1​

</td> <td>

​

</td> <td>

6.26:1​

</td> <td>

12 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

264VO​

</td> <td>

6.06:1​

</td> <td>

3.50:1​

</td> <td>

1.80:1​

</td> <td>

1.00:1​

</td> <td>

0.80:1​

</td> <td>

6.00:1​

</td> <td>

12 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

267V​

</td> <td>

6.06:1​

</td> <td>

3.50:1​

</td> <td>

1.80:1​

</td> <td>

1.18:1​

</td> <td>

1.00:1​

</td> <td>

6.00:1​

</td> <td>

12 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

269V​

</td> <td>

6.06:1​

</td> <td>

3.50:1​

</td> <td>

1.91:1​

</td> <td>

1.18:1​

</td> <td>

1.00:1​

</td> <td>

6.00:1​

</td> <td>

12 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

305V​

</td> <td>

7.00:1​

</td> <td>

3.92:1​

</td> <td>

2.34:1​

</td> <td>

1.42:1​

</td> <td>

1.00:1​

</td> <td>

7.00:1​

</td> <td>

15 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

307V​

</td> <td>

6.27:1​

</td> <td>

3.51:1​

</td> <td>

1.89:1​

</td> <td>

1.18:1​

</td> <td>

1.00:1​

</td> <td>

6.27:1​

</td> <td>

15 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

385V​

</td> <td>

7.01:1​

</td> <td>

3.971:1​

</td> <td>

2.34:1​

</td> <td>

1.42:1​

</td> <td>

1.00:1​

</td> <td>

5.71:1​

</td> <td>

16 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

387V​

</td> <td>

6.27:1​

</td> <td>

3.55:1​

</td> <td>

1.89:1​

</td> <td>

1.18:1​

</td> <td>

1.00:1​

</td> <td>

5.11:1​

</td> <td>

14 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

401V​

</td> <td>

7.07:1​

</td> <td>

4.33:1​

</td> <td>

2.68:1​

</td> <td>

1.64:1​

</td> <td>

1.00:1​

</td> <td>

6.90:1​

</td> <td>

20 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

406V​

</td> <td>

6.61:1​

</td> <td>

3.56:1​

</td> <td>

2.11:1​

</td> <td>

1.43:1​

</td> <td>

1.00:1​

</td> <td>

6.02:1​

</td> <td>

20 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

407V​

</td> <td>

6.61:1​

</td> <td>

3.56:1​

</td> <td>

2.11:1​

</td> <td>

1.43:1​

</td> <td>

1.00:1​

</td> <td>

6.02:1​

</td> <td>

20 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

408V​

</td> <td>

6.17:1​

</td> <td>

3.56:1​

</td> <td>

1.90:1​

</td> <td>

1.16:1​

</td> <td>

1.00:1​

</td> <td>

6.02:1​

</td> <td>

20 pints​

</td> </tr> <tr> <td>

Clark​

</td> <td>

2653​

</td> <td>

7.08:1​

</td> <td>

4.08:1​

</td> <td>

2.23:1​

</td> <td>

1.46:1​

</td> <td>

1.00:1​

</td> <td>

6.73:1​

</td> <td>

12 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

3152A​

</td> <td>

6.00:1​

</td> <td>

3.31:1​

</td> <td>

1.94:1​

</td> <td>

1.16:1​

</td> <td>

1.00:1​

</td> <td>

5.90:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

3153C​

</td> <td>

6.00:1​

</td> <td>

3.31:1​

</td> <td>

1.94:1​

</td> <td>

1.00:1​

</td> <td>

0.79:1​

</td> <td>

5.90:1​

</td> <td>

10 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

5652​

</td> <td>

7.08:1​

</td> <td>

3.83:1​

</td> <td>

2.36:1​

</td> <td>

1.45:1​

</td> <td>

1.00:1​

</td> <td>

7.50:1​

</td> <td>

13 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

5752C​

</td> <td>

6.10:1​

</td> <td>

3.30:1​

</td> <td>

1.81:1​

</td> <td>

1.17:1​

</td> <td>

1.00:1​

</td> <td>

6.46:1​

</td> <td>

13 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

6852G​

</td> <td>

6.70:1​

</td> <td>

3.52:1​

</td> <td>

1.97:1​

</td> <td>

1.17:1​

</td> <td>

1.00:1​

</td> <td>

6.72:1​

</td> <td>

17 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

6852K​

</td> <td>

6.72:1​

</td> <td>

4.02:1​

</td> <td>

2.49:1​

</td> <td>

1.57:1​

</td> <td>

1.00:1​

</td> <td>

6.72:1​

</td> <td>

17 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

6852S​

</td> <td>

5.71:1​

</td> <td>

3.21:1​

</td> <td>

1.89:1​

</td> <td>

1.15:1​

</td> <td>

1.00:1​

</td> <td>

5.73:1​

</td> <td>

17 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

6853C​

</td> <td>

5.71:1​

</td> <td>

3.02:1​

</td> <td>

1.78:1​

</td> <td>

1.00:1​

</td> <td>

0.86:1​

</td> <td>

5.73:1​

</td> <td>

17 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

8052, 8045*​

</td> <td>

7.30​

</td> <td>

4.54:1​

</td> <td>

2.75:1​

</td> <td>

1.65:1​

</td> <td>

1.00:1​

</td> <td>

7.00:1​

</td> <td>

24 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

8052B​

</td> <td>

7.30​

</td> <td>

4.54:1​

</td> <td>

2.75:1​

</td> <td>

1.56:1​

</td> <td>

1.00:1​

</td> <td>

7.00:1​

</td> <td>

24 pints​

</td> </tr> <tr> <td>

****er​

</td> <td>

8052D​

</td> <td>

7.30​

</td> <td>

4.17:1​

</td> <td>

2.52:1​

</td> <td>

1.56:1​

</td> <td>

1.00:1​

</td> <td>

7.00:1​

</td> <td>

24 pints​

</td> </tr> </tbody></table>

​

 

Sure are! They each weigh a ton. Rods and pistons together are easily 10 lbs.

It is the baby of the family, but it was free!

I'm thinking it's got about 10k on a rebuild. Pistons are .040 over

It's getting two turbos from some Mercedes diesels! I'm only going to push about 8 - 10 psi into it, though.

 

My pops just picked up a 63 GMC with the 305. Original motor that has never been out of the truck and it still runs great. Has a cool sound to it also.

 

love those gmc big block v6's

 

My buddy has an all original 1960 GMC 1000 truck, with 305 engine that is restored right now.
What a fine piece of a 60s truck ....

On this page http://www.6066gmcguy.org/V6powered.htm is a T-bucket with 305 ....



2 1/2 by 3 1/2 square ch***is; Chevy 12 bolt 3.73 rearend; '64 Impala SS 3sp ******.


same page also shows this:



GM Futurliner #11, One of 12 built by GMC Yellow Coach, is self-contained display & transport vehicle created by the GM design staff under Harley Earl's direction.

 

I see a lot of people stated these were gas hogs. My 305 v6 in my 62 chevy got 21mpg. The 235 blue flame it had got 21mpg....I guess I missed the gas hog part? Anyway, I now have a 478 in a big truck, do you have some place you found parts for this?

 

Arent those a 2 1/2" bore, 4 1/2" stroke ?