Thread: Engine Advice!!!!

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Originally Posted by Dave Severson

I'm by no means one of the sbc guru's on here, but I do think that's way too much cam for those heads!!!! You're right on the engine parts, they do have to match!!! Regardless of the brand, over-camming and over-carbing are probably the two most common mistakes on engine builds..... All the components have to compliment each other to get the most out of an engine.

Any SBC gurus on here that could guide me to the cam that would work well with these heads?

Originally Posted by Dave Severson

I'm by no means one of the sbc guru's on here, but I do think that's way too much cam for those heads!!!! You're right on the engine parts, they do have to match!!! Regardless of the brand, over-camming and over-carbing are probably the two most common mistakes on engine builds..... All the components have to compliment each other to get the most out of an engine.

Maybe there will be a sbc guru that will be able to point me to the right cam for these heads!! Hint Hint

Welcome to CHR Clayton:

I’ve read this thread and also your PM to me and I think you may have pretty good base but I have a couple questions and comments.
1. Do you know if you had the block squared? If so, do you know the finished deck height (it will be a 9.xx number).
2. You said that you had the heads milled. Why? Were they not square or were you looking to increase c/r?
3. What head gasket have you been using (how thick?)
4. You indicated that you had 10:1 c/r – how was that determined?
5. Is this an automatic or manual transmission?
6. Do you know the rear end ratio?

Couple suggestions:
1. Do not port these heads – you will not improve them and in all likelihood hurt performance. These are some of the best flowing factory heads ever made by GM.
2. You probably have too much lift, but need to know more about the cam to know if you’re “over cammed”. I would recommend something like this one - Summit Racing Street & Strip® Cam Kits SUM-K00042, 210/210 @050 and .440/.440 lift.
3. Edelbrock Performer is okay, Performer RPM manifold is better. The 1406 is also fine (IMO) but if you change to a Performer RPM, I’d go to a spread bore and use a Q-jet, but I like Q-jets and that big rush when the secondaries open.

As mentioned by others, your bent push rods may be valve float.

Regards,
Glenn

Glenn, all this took place 12 yrs ago so I will try my best.

1. I know when I took the block to the machinist he bored the block .040 and checked it to see if it needed to be squared. I don't remember if he needed to do that or not (If it needed to be done he did it) so I don't have that 9.xx number.
2. I milled the heads because a friend suggested doing so to increase compression ratio. I will leave the ports alone if they are fine as is and paying to port and polish them will be a waste of money. Do you suggest I change the valve springs and rockers?
3. I probably bought some cheap head gaskets when I was 18 because I was broke so assume the worst. I can change those out to whatever they need to be.
4. I don't know the actual compression ratio in the engine itself but the pistons I bought said 10:1 C/R. Is there a way I can check the actual C/R?
5. I have a Turbo350 transmission with a 3000 stall.
6. The rearend was replaced with a stock 10 bolt (one wheel pulling) but I am planning on going with a eaton posi with 3.73 gears unless suggested otherwise.

I have headers on the engine that go back to dual 3" flowmasters.

I had all the specs on the cam when I built it but since lost all the information once I moved away from home. Will that cam you suggested still have a good sounding lope to it? I would like to have a good sound with the best performance.

I think my dad may have a Edelbrock Performer RPM manifold in his shop.

Is the carb you suggested for the RPM manifold a Qjet brand? Sorry for my lack of knowledge.

intake or exhaust pushrod ?

Originally Posted by HOSS429

intake or exhaust pushrod ?

ummmm, not sure. It's the one that sits in the lifter and goes up to the rocker.....

The cam that I have is a Crane Cam with 238 int / 244 exh @ 050 in lift with 0.502 int / .0516 exh lift lobe separation of 106 degrees. Now that I have the specifics on the cam lets say that the heads are just out of the box Vortec 12558062 heads with 1.94/1.50 valves with 64cc chambers. Would this be too much cam for these heads? I did have the heads milled to increase c/r but can't remember how much.

You need to go back to the basics to check out what you have and its total relationship with the other components of your engine---heads milled to increase compression-----effects valve to piston relationship (clearance)
Cam---cam timing to crank effects valve to piston relationship(clearance)
Heads---clearance between valve retainer, seal, guide effects how much cam lift can be used
Valve springs--spring pressure effects tappet following cam lobe and rpm---

Originally Posted by jerry clayton

You need to go back to the basics to check out what you have and its total relationship with the other components of your engine---

Thanks Jerry, that's pretty much what I told this young man on another forum. For instance, you can't choose another cam until you know the static compression ratio.

Thanks guys, looks like I have my work cut out for me!