Old School SBC Help!

[pretentious_pontiac]

So good news. I did the old spark plug out and used a skinny rod to measure tdc and lowest stroke and it is in fact 3.75” and there is only 2 freeze plugs on the side without a indent for another so I’m pretty sure it’s a 383 stroker. Now just to figure out what heads they put on and I’ll get all the info I care to have. I just love learning more about these engines. I wanna be THAT guy who is a guru at it when I’m older.

 

[ELCAM]

Two ways to help ID the heads. On the front of the heads look for these marks.

Pull the valve cover and look for the actual casting number.

Top is casting number, bottom is date code. Letter is month no "I" ( could be confused with a 1) a = Jan etc. 17th day, 5th year. Year has to be determined by casting number and other features since it could be 55, 65, 75 or 85.

Also if taking off the valve cover look for screw in rocker studs and guide plates for the pushrods. Low performance engines had press in rocker studs and old school trick on these was to drill through the side of the boss that the stud was pressed into and through the stud allowing putting pins in them so high lift cams would not pull the press in studs out.

When talking casting numbers for heads the last three numbers are usually used since GM never repeated them. So the above are 461 heads.

One thing for determining the year is the accessory bolt holes in the ends of the heads. 1955 - 1967 no holes.

Later heads have accessory bolt holes 1, 2 or 3 depends on the head some have one hole on the back and 3 on the front so you have to keep track when installing them. 68- 86.

 

[pagrunt]

One thing for determining the year is the accessory bolt holes in the ends of the heads. 1955 - 1967 no holes.

'69 was the first year for heads to have accessory bolt holes. I had a '68 307 that didn't have the bolt holes. A freind years back had a '68 Chevelle that also had a 307 with out the bolt holes.

 

[pretentious_pontiac]

I’ll definitely have to look for that. I’ve got some pictures of when I took the covers off but nothing too useful I don’t think.

 

[ELCAM]

Those are 882 small block 350 - 400 heads . They were cast June 10th 1970 so probably from a 350 since the 400 didn't come out till 71 model year. If I remember correctly these are 76 cc combustion chambers. 1.94" intake valves and 1.5" exhaust valves.

 

[pretentious_pontiac]

Those are 882 small block 350 - 400 heads . They were cast June 10th 1970 so probably from a 350 since the 400 didn't come out till 71 model year. If I remember correctly these are 76 cc combustion chambers. 1.94" intake valves and 1.5" exhaust valves.

That’s what I figured. I know the push rods are much thicker than stock and it looks like stiffer springs but I don’t remember how stock looks. I took apart a 350 before. I’m assuming it was all part of a cam kit from jegs. (It’s got 2 huge jegs stickers on the inside hood)

 

[ELCAM]

Oops May 10th 1970.

 

[64nailhead]

If you think this runs well now, then upgrading from the 882’s will feel like you added 100hp.

 

[bracketchev1221]

That’s what I figured. I know the push rods are much thicker than stock and it looks like stiffer springs but I don’t remember how stock looks. I took apart a 350 before. I’m assuming it was all part of a cam kit from jegs. (It’s got 2 huge jegs stickers on the inside hood)

Actually to me it looks stock with stock type springs and no guideplates. Possibly even press in studs.

 

[64nailhead]

Actually to me it looks stock with stock type springs and no guideplates. Possibly even press in studs.

Agree, looks iffy at best.