69 Blazer

[70shortfleet]

I just bought a 69 Blazer and I'm wondering what engine is in it, the code on the block is: F0721TLS and under that is T7S529657 does anyone have an Idea what engine this is, the engine really close to the firewall and can't see what the number is on the back of the motor! thanks for any help

[Mike C]

Nasty Z/28 says that suffix is for a ‘75-‘77-‘79 400 small block. How many freeze plug bosses are on the side of the block?

[70shortfleet]

really hard to see anything on the right, with the motor mount and headers I can't even see 1 freeze plug

[70shortfleet]

This transfer case is in my 69 Blazer, is this original for 69 Blazer? It has Dana c18-15-38 on it, thanks for any help

[57taskforce]

Yes the Dana 20 was available in 69

[Steeveedee]

I believe one can see the reliefs in the pan for the rods on an SBC 400. If you have an engine handy that is known NOT to be a 400 you can make a comparison from underneath?

[70shortfleet]

Originally Posted by 57taskforce

Yes the Dana 20 was available in 69

I was wondering because it has a 4 speed saginaw in front of it which I don't think factory

[70shortfleet]

Originally Posted by Steeveedee

I believe one can see the reliefs in the pan for the rods on an SBC 400. If you have an engine handy that is known NOT to be a 400 you can make a comparison from underneath?

both of my other trucks have big blocks in them.

[57taskforce]

Look at the harmonic balancer. SBC 400 is externally balanced. All other small blocks are internally balanced. The balancer will likely look like that of one of your big blocks, and be totally different than all other small block balancers. Also I’m pretty sure the Saginaw was available in the 69 blazer and was exclusively paired to the Dana case. I think every other tranny option got the 205, as it was introduced in the 69 blazer as far as GM stuff goes.

[70shortfleet]

here is a picture of the saginaw in front of the Dana transfer

[70shortfleet]

Would there be a high hump made for this set up?

[57taskforce]

You can make any 67-72 high hump work, you’d just have to patch/cut where needed. Finding that particular one with the cut outs in the right place is probably not going to be easy, as that’s not a terribly common setup.

[70shortfleet]

It does have a high hump in it but it looks like someone butchered it and the harmonic balancer does look like the ones in my big block trucks. It needs a new clutch so I have to pull everything apart, not a fun thing to do laying on your back