[tomaszek]

I can’t read the code on the middle exhaust port. Rusted off. So I took a picture. Any chance you can guess. The block is a 70 350. Has some codes on sides. H218 on one. 1048 on the other. Both have a D and D. And one of the exhaust ports have a G on it. I have a set in the shed which will try and get numbers for. If I’m rebuilding I’d like to use the best. Basically just stock 350 bored over 60 with a mild can. Nothing special. Thanks.

[steve25]

Looks like there original to 1970 which would have been a casting #11 with a 2bbl intake and the 254 2bbl cam would have been in the motor .

Compression was stated as being 8.8, but more likely it was closer to 8.2.

[steve25]

Looks like there original to 1970 which would have been a casting #11 with a 2bbl intake and the 254 2bbl cam would have been in the motor .

Compression was stated as being 8.8, but more likely it was closer to 8.2.

The heads have pressed in rocker studs, so don’t be like me back in the mid 80s and find out that if you do not want to snap off the tops of the studs you can’t run more then a .450” lift cam.

[242177P]

Originally Posted by steve25

Looks like there original to 1970 ...

Not with those date codes they aren't. H218 is August 29,
1968 while I108 is September 10, 1968. The early 1969 dates
suggest they could be #47. Is it actually a 69 350?

[steve25]

Whoops!

Sorry!

When you enlarge the heck out of the photo you can make out a 4 on the front center exh pad.

So they where cast as they should be without the air injection boss in late enough 68 for them to be used in 1969 production.

They have 1.96” / 1.66” valves with pressed in studs, and they also do not have the end exh flange bolt holes drilled.

Also note that a stock 350 is really 354 cid so I would think twice about going .060” over unless you have the pistons already or the bores need to go .060”.

[tomaszek]

Here is the block code

[tomaszek]

The engine was rebuild back when I got it. The guy said it was either 30 or 60 bored over. I can’t remember. Not sure if any of these kit numbers during the rebuild help.

A push rod says rp3028 on the rod itself.

So based on the different stamps on each head. Do I have two unrelated heads installed ?

[tomaszek]

Inside head just in case it helps

[b-man]

1969 350 with 1969 #47 350 heads as one would expect according to head dates and the YU block code.

There you go.

[steve25]

So from that receipt it look like the heads got new valve springs, two new valves, new push rods and new rocker arms.

Both heads on any factory motor rarely have the same casting dates.

The block code YU means it came out of a A body automatic car ( Tempest/ GTO ) and was rated at 265 Hp with its 2 bbl carb.

[tomaszek]

Is the picture I posted not the block code ? I think it’s a 70 block.

[b-man]

The YU block code was used for 1969 265 HP 2-barrel 350 and 1971 250 HP 2-barrel 350 as well so it’s not a 1970 350.

The block date code is cast at the top rear near the distributor hole.

[tomaszek]

Here’s by distributor

[srmmmm]

Originally Posted by steve25

Whoops!


Also note that a stock 350 is really 354 cid so I would think twice about going .060” over unless you have the pistons already or the bores need to go .060”.

I went .060" over on mine with no issues and have been told that the 350 block could handle an .080" if necessary. Now, I'm not sure if it's model year dependent or not, but the 350 block is no lightweight compared to other GM divisions' 350's.

[242177P]

Originally Posted by tomaszek

Here’s by distributor

J299. October, 1969. So a 70 350, with heads off of a 69 350.
I expect the block casting number (behind the passenger
head) will be 9799916.

[tomaszek]

Yup you are correct that’s the number on the passenger side. Thanks for all the info.

Just to confirm. These are 47 heads ?