[67GTO4SPEED]

A friend of mine buys and parts out old trucks, and he came across these out in the country. The guy that owned them inherited them from his father. He is not a car guy, and just wanted to move the stuff. He had a '65 GTO and '69 Grand Prix SJ that he had already sold for pretty good money, and what we bought was the leftover "junk" as he called it. -lol We bought a rusty '69 Grand Prix J that has 350HP 400 with #62 heads, and the '68 428 was in the garage. He said the 428 was pulled out of a wrecked car "many" years ago. My buddy and I went together and bought all of of it. He wanted the Grand Prix body because he has a Chevelle that needs the disc brakes, floor shift column, and bucket seats. I got the 428, the 400 with TH400 trans, and the Rallye II's off the GP. I am ashamed to tell you guys how much money I have in these!

I pulled the 428 apart today and it looks great inside. I am going to use this block for my GTO instead of the '76 455 I already have. It has a slight ridge, so I'll have it bored and decked, but I was going to have that done on my 455 anyway. Now I have to decide if in want to use the 455 crank or stick with the 428. For some reason, I have always wanted to build a 428 since you rarely see them. Whichever one I build will be running these heads: http://forums.maxperformanceinc.com/...=736029&page=2


I noticed something kind of odd - this block doesn't have "428" cast into the side or "28" cast in the lifter webbing. I've always read that started in '68, but it must be an either/or thing that year. It is a YH code engine with a 9792968 casting number with a F048 date code. The heads are #46 and crank is casting number 9782769 with "N" nodular marking.

This leads to a question: Are the Alt, P/S, and A/C brackets the same on a '69 GP engine as thery would be on a my '67 GTO? My GTO has '73 model 400 in it now, and they are different.

[gtofreek]

Nice score! Sounds like you have an early production 69 428 engine there. I'm betting it has 2 bolt mains also. That should be a 360 HP 1969 engine. All 67 and 68 428's were 4 bolt mains. 69 low perf engines had 2 bolt mains. The #46 heads are low perf, small valve heads with pressed it rockers. The 68 375 HP 428 should have had #16 heads on it.

Still a very nice find and the 428's really scream! The #46 heads make killer sleeper heads if you have them properly opened up to 2.11/1.77" valves and have screw-in studs installed.

[67GTO4SPEED]

Originally Posted by gtofreek

Nice score! Sounds like you have an early production 69 428 engine there. I'm betting it has 2 bolt mains also. That should be a 360 HP 1969 engine. All 67 and 68 428's were 4 bolt mains. 69 low perf engines had 2 bolt mains. The #46 heads are low perf, small valve heads with pressed it rockers. The 68 375 HP 428 should have had #16 heads on it.

Still a very nice find and the 428's really scream! The #46 heads make killer sleeper heads if you have them properly opened up to 2.11/1.77" valves and have screw-in studs installed.

Ok, that makes sense. Oddly enough, these #46's have screw in studs, which I've never seen before. I've had 2 different 69 Pontiacs with 290HP 400's, and both of them had pressed in stud #46's. I'll definitely put them on the shelf for a future project maybe.

The heads I'm going to use are a set of '68 #16's that were ported by Steve Magnotti (Steve25) to flow 265/208. I'm thinking about sticking with 428. My GTO has a 4 speed(that is going to eventually going get a TKO700) and I've seen a lot of people say the 428 revs a little bit better than a 455. Another factor I am dealing with is that my '76 model 455 does not have the nodular crank. It also seems that getting a 428 to a streetable CR with the #16 heads is a little easier than with a 455 (a lot smaller dish in the piston).

As of now, I have this 428, the '76 455, (2) (a '68 and a '69) XH code 350HP 400's, and a '73 400. With the money I have spent (and am still spending) on restoring the car, a 400 stroker is not in my budget. That leaves me with building either this 428, this 428 block with the regular cast iron 455 crank, OR the '76 455 block with 455 crank.
It's looking like this 428 with the nodular crank is the best engine I have. I haven't mic'd everything yet, but all of the bearings looked fantastic, and it came out of a running car. I already have a new set of forged rods. I have a set of KB Hyper 455 30cc dished pistons, but I have talked myself out of running them. I can exchange them at Summit, and I thought about going with the Speed Pro forged 428 15 cc dished pistons that they have.

What are your thoughts on that?

[screamingchief]

Originally Posted by 67GTO4SPEED

Oddly enough, these #46's have screw in studs, which I've never seen before.

Check the date codes on those heads,could easily be late '73-'74 #46 350 cid small valve heads,as mid year '73 they went to screw in studs for all heads,even the 350 cid small valve #46 heads.

Someone could've easily thrown a set of those on the 428 shortblock to make it more pump fuel friendly as the 350 cid smog heads would've been 89-92 or so cc's as SOP.

Honestly,if they are the "smog era" 350 cid #46 small valve/SIS heads,they could make a very usable set of heads for a true "flat top" 428 combo.

Originally Posted by 67GTO4SPEED

I have a set of KB Hyper 455 30cc dished pistons, but I have talked myself out of running them.

Good call,cause next to the POS 8vr cast 400 pistons being the worst pontiac piston choice out there,my POV holds that the KB hypers are almost as bad of a piston choice.

Pistons just are'nt a good thing to cut corners on.

Originally Posted by 67GTO4SPEED

It also seems that getting a 428 to a streetable CR with the #16 heads is a little easier than with a 455 (a lot smaller dish in the piston).

Still gonna take a decent dish to get the CR @/below 10:1 or thereabouts,so yeah it'll take like 15 cc's of dish to do that,and 20'ish cc's if you want to get it down around 9.5:1 CR.

So the 15cc dished FM forgings may indeed be a decent option to look into.

Nice score,good luck with the builds.

FWIW

Bret P.

[67gtospud]

Originally Posted by gtofreek

Nice score! Sounds like you have an early production 69 428 engine there. I'm betting it has 2 bolt mains also. That should be a 360 HP 1969 engine. All 67 and 68 428's were 4 bolt mains. 69 low perf engines had 2 bolt mains. The #46 heads are low perf, small valve heads with pressed it rockers. The 68 375 HP 428 should have had #16 heads on it.

Still a very nice find and the 428's really scream! The #46 heads make killer sleeper heads if you have them properly opened up to 2.11/1.77" valves and have screw-in studs installed.

What's the proper way to open up #46 heads? I've got a set that I'm going to be running on my 400. I will be converting to screw in studs.

[gtofreek]

Using a radius seat cutter on the exhaust so there is a venturi under the valve seat angle. Factory big valve heads just go from a 45° seat, straight into a 90° throat. This is not good for flow. Too much angle change to make the turn easy. A radiused venturi, or even just another angle like 60° under the 45° seat angle will help a bunch.

A 3 angle job on the intake, followed up by a 70° throat will be good on the intake. I like to use a 30° intake seat for flat tappet cams.

There are 1974 350 heads out there with the #46 casting numbers that had screw-in studs, but it seems like the outside of the exhaust port is different than what you picture. To me, your heads look like 69 era castings. Best to check the casting dates to be sure. The 69 castings have a smaller chamber.

[67gtospud]

Originally Posted by gtofreek

Using a radius seat cutter on the exhaust so there is a venturi under the valve seat angle. Factory big valve heads just go from a 45° seat, straight into a 90° throat. This is not good for flow. Too much angle change to make the turn easy. A radiused venturi, or even just another angle like 60° under the 45° seat angle will help a bunch.

A 3 angle job on the intake, followed up by a 70° throat will be good on the intake. I like to use a 30° intake seat for flat tappet cams.

There are 1974 350 heads out there with the #46 casting numbers that had screw-in studs, but it seems like the outside of the exhaust port is different than what you picture. To me, your heads look like 69 era castings. Best to check the casting dates to be sure. The 69 castings have a smaller chamber.

a picture is worth a thousand words lol

[gtofreek]

Here is two pics. The first is a radiused cut. The second is a 3 angle valve job. These are Kauffman D-port heads for a twin turbo 400.

[67GTO4SPEED]

These are the correct '68 (probably late '69 as gtofreek said) date coded small chamber heads. This engine has never been apart as far I can tell. It had all factory gaskets and had the little tabs bent of the manifold bolts, etc.

[HWYSTR455]

Originally Posted by 67GTO4SPEED

....

This leads to a question: Are the Alt, P/S, and A/C brackets the same on a '69 GP engine as thery would be on a my '67 GTO? My GTO has '73 model 400 in it now, and they are different.

67 was a cutover year, if I recall correctly, and there was a mix of acc brackets used, think it depended on the model of car. It will depend on the TC and WP you use, 68-up for sure was 11 bolt. I personally prefer the 68-70 A/C big car brackets and pulleys, they sit low on the engine, allow use of earlier heads, and are great for cooling. Believe 71 is when they went to the extra hole in the heads, and the alt mounted higher. Early heads (pre-71) don't have the provision for those brackets, and you will be forced to use the 70 and before brackets. (Like on your 16s)

I did at one time post all the matching pulley numbers for the big car setup, could probably search it here.

I like the fact you are going down the 428 road!

.

[67GTO4SPEED]

I took some pics of one of the heads. It is coded H288 (which is consistent with the block date code) and has screw in studs. I guess it goes to show the inconsistencies that came from the factory back then. As I said before, about 99% sure this engine has never been apart.

[gtofreek]

Your not saying it has screw-in studs because of the nuts on the rocker arms are you? Screw-in studs have an 11/16' hex at the base of the stud, against the head. Usually these heads have a small bolt holding the guide plate to the head, and pressed in studs.

[screamingchief]

Those dont look like screw in studs to me.

Agree they're likely the '69 400/428 small valve heads from the date codes,but those are gonna be pressed stud heads as SOP,and if they dont have pressed studs now,then someone had to have pulled them off @ some point and have them converted to SIS.

The factory did'nt do any screw in stud/small valve heads till mid year '73,that's not even up for debate IMO,it's a given.

Guideplates dont = screw in studs.

Pull a rocker off and then you'll see.

Bret P.

[demonic68]

Nice find man I have always liked the 428 to for some reason

[Cliff R]

The 428 will be the 360hp engine for 1969 with the small valve #46 heads, all have been two bolt mains from what I've seen to date, with log manifolds.

The 375hp engines will have 4 bolt mains, big valve heads with screw in studs, and long branch manifolds with a different oil filter housing.

The #46 heads are nice heads, we have used quite a few sets of them here over the years. We even installed a set on a fresh 455 shortblock two years ago just to meet the deadline to get a car ready for Norwalk.

We just cleaned up the heads, and converted them to screw in studs. Didn't port them anyplace, not even a gasket match. Re-used the small valves (45 degree seat intakes) and added a set of Crower springs. With a used flat tappet Crower cam we had under the workbench, the 455 pushed a 1981 Firebird to high 11's at 112mph in hot/humid August weather.

The same #46 heads are out right now for 2.11/1.77 valves for a 400 build we doing next month. They are excellent heads, and as good as any other "D" port offering from that era......Cliff