Anything new from the straight 8 hot rodders?

[36 Century]

A custom crank with 9 main webs!!! Bryan, I assume your family runs a machine shop? I wish mine would, too!
Now bear with me, my head is exploding with questions

Let's start with your yellow coupe. You must be running around 400 HP.

PISTONS. Did I get it right - you are running International (cast) pistons that give you 3.687" bore and 11.5 CR ? Is that with .25" off head and deck combined, and copper gasket? Did you make any mods on the pistons?

CRANK & RODS: Are you running stock crank and rods?

CAMSHAFT: Who ground it, and if you wish to reveal specs, let's go for it!

LIFTERS, PUSHRODS and ROCKERS: Are you running stock lifters? I bet you made your own pushrods? And finally, do you have those Cadillac 1.7 rockers? Do the valves come close to pistons?

OVERSIZE VALVES: I'm using BB Chevy, some are using Cadillac. What are you using?

PORTING: I assume you didn't just pocket-port, but enlarged the ports all the way, right? What kind of exhaust-to-intake flow percentage did you get? How did you address the flat back wall between the siamesed intake ports?

Pistons in the YELLOW coupe are 3.625" diameter, which is the 220 international pistons, .060" over. they are fully machined on the dome to accept the combustion chamber of the buick. The wrist pin diameter is the same as buick. The rings for the international pistons are WAY too thick at around 5/32" if I remember correctly. I made aluminum inserts that went in the international ring lands, then re-machined the inserts to accept a .062" thickness compression ring, and 4mm oil ring. This GREATLY reduces the friction as well as I can buy rings at nearly any auto wherehouse.

Yes I run a SOLID copper head gasket with .025" quench pad from the piston to the head.

Crank is stock, rods are stock rods that have a T-1 plate bolted in the original gap, then a grade eight bolt bolted in the bolt hole of the small end of the rod, then torqued down and loctited. I then machine out the portion of the bolt that is left in the pin bore and bush the rod for a full floating pin. I will not weld on a rod, for metalurgy reasons.

The camshaft in the Yellow coupe is a LDB Isky Cam, track 2 grind. It works well to about 6k. The drag/bonniville car motor has a CRANE cam grind in it. It is a SBC grind out of all things. It is fairly radical, and tough on the street.

Lifters. I use SBC lifters in the yellow coupe, I bused the block with bronze bushings to use these lifters. In the Drag motor I use Mopar mushroom lifters, with a small sleeve pressed on the lifter to come out to the 1" diameter needed for the buick block. I made my own chromolly push rods, using stock ends. You can use GMC lifters after they are metal sprayed or hard chromed as they are .990" stock. My piston to valve clearence is .050" on the intake, and .090" on the Ex. The yellow coupe has stock valves in it, the drag motor has speacial .3125" diamter stems, forget what they come out of, as We have a master valve book, and we just go by dimensions and part numbers. On the Cad rockers, I belive V-12, but Ill have to check and verify that.

On porting, they are fully ported heads on both motors, and also brazed in alot of the spots. The intakes I bore straight down to enlarge on the mill, then hand grind from there. EX are brazed in the roofs as well as We grind them way to thin for a gasket to work between the head and the header. I belive we are at a 73% intake to ex comparison, I will have to dig up my flow bench numbers to verify that as well, as it has been awhile. We have experienced with using a divider in the port to get rid of the 4 port design, and it seems to work well, but we have not ran it on a can yet. We are also making a fully billet alluminum head, actually bought the chunk of 6061, as well as started the cad work on that as well, but we are still playing with CFD testing for port design.

[36 Century]

Hey 36 Century, I'm curious if there's a difference in the sound of the engine when comparing the tuned 360-degree header and the conventional header?

What I mean is, when you bring cylinders # 1-4 into one collector and #5-8 into another, basically you get two rather odd-firing engines, sound-wise. This is what I have, and it sounds nice. Whereas arranging primary tubes based on firing order, provides a more even-firing engine, sound-wise. Now this is all theory, and you have the opportunity to verify if this is true or false?

Yes there is a big difference in sound, but it is hard to tell as the cams are so different. The drag motor with the tuned header does sound a bit more "smooth" with the firing pulses than the orange headers though.

[Jyrki]

I use SBC lifters in the yellow coupe, I bused the block with bronze bushings to use these lifters. In the Drag motor I use Mopar mushroom lifters, with a small sleeve pressed on the lifter to come out to the 1" diameter needed for the buick block.

What do you have against using standard Buick lifters? As far as I understand, the cam can be ground with faster ramps when using large diameter lifters?
Anyways, a humble thanks - this information is invaluable

All the folks on this forum, take note: Bryan is willing to go into detail to benefit this community. We are here to share information and experience, not just to private mail or to throw some general comments for bragging rights.

[Jyrki]

Bryan, it surprises me you're going to whittle a custom crank and head out of a billet blank, but you never made any roller rockers! I'm sure your shop could manufacture a set of hi-lift roller rockers pretty easily, or better yet, a short production run...

I wonder how difficult would it be to purchase a few bars of extruded aluminum blanks from one of the rocker mfg's out there?

[JR9162]

Bryan, it surprises me you're going to whittle a custom crank and head out of a billet blank, but you never made any roller rockers! I'm sure your shop could manufacture a set of hi-lift roller rockers pretty easily, or better yet, a short production run...

I wonder how difficult would it be to purchase a few bars of extruded aluminum blanks from one of the rocker mfg's out there?

What about the guy who makes roller rocker arms for Nailhead Buicks?

[Jyrki]

What about the guy who makes roller rocker arms for Nailhead Buicks?

I wasn't aware of such man. Can you tell me a little bit more, please?

[Aaron65]

He's Tom Telesco, or telriv on this site...

36 Century...you are the man...I'm always jealous of the things good machinists can do...

[52rat]

Hey 36 Century, I'm curious if there's a difference in the sound of the engine when comparing the tuned 360-degree header and the conventional header?

What I mean is, when you bring cylinders # 1-4 into one collector and #5-8 into another, basically you get two rather odd-firing engines, sound-wise. This is what I have, and it sounds nice. Whereas arranging primary tubes based on firing order, provides a more even-firing engine, sound-wise. Now this is all theory, and you have the opportunity to verify if this is true or false?

I have my # 1-4 into one collector and # 5-8 into another, and I have to agree, it sounds great. Kind of like a drag car when I have my dump caps off. Great stuff!

[39CENT]

Thanks for the info, 39 Cent. It seems this company can rebuild your existing rocker assembly, but they are not manufacturing them, at least not for our str-8's

I really would like get my hands in a large inventory on rocker arms for multiple makes. I'm pretty sure something could be adopted to fit a Buick

Looking at the 'Rocker Arm Specialist' site they show a extruded rocker arm similar to a buick strt 8, Its a longer arm for an Austin Healey. Might be able to get blanks, or get someone to make a profile 'loaf' , and then slice off rocker blanks like from a loaf of bread.

[36 Century]

You know what, I think I will tool up my CNC to build a set or two of rocker arms. I am thinking of about a 1.6-1 ratio. I can build them all out of billet, without a problem. How many of you guys might be interested. I will build a couple and post pics, to see what you guys think.