Thread: A few build questions

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I am in the process of putting together (as I mentioned before) a standard little SB350. I had some questions for the build.

First of all, how much lift can some GM Cast# 882 heads take with new springs?

The springs that were reccomended to me were:
Valve Springs, Single, 1.254 in. Outside Diameter, 417 lbs./in. Rate, 1.150 in. Coil Bind Height

I ask this because I messed up on a summit order, and they sent me two cams:

12-238-2:
Grind Number CS XE262H-10
Valve Adjustment 0 0
Gross Valve Lift 0.462/0.469
Duration At 0.006 Tappet Lift 262/270

Valve Timing At 0.006
Open / Close
Intake 25 / 57
Exhaust 69 / 21

12-246-3:
Grind Number: CS XE274H-10
Gross Valve Lift 487/490
Duration At 0.006 Tappet Lift 274/286

Valve Timing At 0.006
Open / Close
Intake 31 / 63
Exhaust 77 / 29

Which of these cams should I keep? I plan on running a ~2000 stall into a built TH350 with a 3.23 posi rear end. Compression ratio will be whatever the stock bottom end, plus the large 76cc chambers of the 882s equate to.

Another question: When removing the rocker arms from said heads, the stud that the rocker arms sit on were stripped on about 4 studs. I ordered some ARP 7104 rocker-arm studs as reccomended to me. Now, the stock rocker arm bolts just go into the head, how would I pull that bolt out to put the new studs in?

Finally, If just dropping in a cam/lifter kit, and a gear drive timing set up, what all needs to be replaced (besides gaskets, obviously) while the motor is on the stand with the bottom end intact? Where all do I need to apply assembly lube? I want to do this right.

Thanks in advance for any help, this is a first for me.

Originally posted by SBC Maro
I am in the process of putting together (as I mentioned before) a standard little SB350. I had some questions for the build.

First of all, how much lift can some GM Cast# 882 heads take with new springs?

The springs that were reccomended to me were:
Valve Springs, Single, 1.254 in. Outside Diameter, 417 lbs./in. Rate, 1.150 in. Coil Bind Height

I ask this because I messed up on a summit order, and they sent me two cams:

12-238-2:
Grind Number CS XE262H-10
Valve Adjustment 0 0
Gross Valve Lift 0.462/0.469
Duration At 0.006 Tappet Lift 262/270

Valve Timing At 0.006
Open / Close
Intake 25 / 57
Exhaust 69 / 21

12-246-3:
Grind Number: CS XE274H-10
Gross Valve Lift 487/490
Duration At 0.006 Tappet Lift 274/286

Valve Timing At 0.006
Open / Close
Intake 31 / 63
Exhaust 77 / 29

Which of these cams should I keep? I plan on running a ~2000 stall into a built TH350 with a 3.23 posi rear end. Compression ratio will be whatever the stock bottom end, plus the large 76cc chambers of the 882s equate to.

Another question: When removing the rocker arms from said heads, the stud that the rocker arms sit on were stripped on about 4 studs. I ordered some ARP 7104 rocker-arm studs as reccomended to me. Now, the stock rocker arm bolts just go into the head, how would I pull that bolt out to put the new studs in?

Finally, If just dropping in a cam/lifter kit, and a gear drive timing set up, what all needs to be replaced (besides gaskets, obviously) while the motor is on the stand with the bottom end intact? Where all do I need to apply assembly lube? I want to do this right.

Thanks in advance for any help, this is a first for me.

What is the open pressure and at what height?What is the closed pressure and at what height?

981-16

O.D.: 1.065/1.240
I.D.: 0.650/0.825
Seat Load: 110 @ 1.700
Open Load: 301 @ 1.150
Coil Bind: 1.115
Rate(lbs./in.): 347
TitaniumRetainer: 788
SteelRetainer: 787
Cup/Seat: N/A
Shims: 4753

Neither cam will work. You have insufficient static compression ratio to support either one.

Go-Go Summit Techs : / Would someone advise a cam? Frustrating that the people that are payed to give help are useless compared to the experianced people on these forums.

I was planning on going with some Iron Eagle heads further down the road, some 64cc chambered ones.

Your present c.r. is about 8.3:1 which will support something like the XE250H at most.

With all else being equal, a change to 64 cc heads will result in a static c.r. of 9.5:1 and you would be able to run either of the cams you have on hand. However..........

You will not be able to run 9.5 c.r. with iron heads on pump gas without minimizing the squish to around 0.035" to 0.040". That means a complete teardown and decking of the block. You may squeak by with aluminum heads without the teardown.

This is just my opinion based on 50 years of hot rodding, others may have a different opinion.

"This is just my opinion based on 50 years of hot rodding, others may have a different opinion."

I am going to have to take your advice on this one, I respect experiance.

minimizing the squish to around 0.035" to 0.040"

Can you expain that?

Originally posted by SBC Maro
Go-Go Summit Techs : / Would someone advise a cam? Frustrating that the people that are payed to give help are useless compared to the experianced people on these forums.

I was planning on going with some Iron Eagle heads further down the road, some 64cc chambered ones.

If you put the 64 cc heads on this will give you the comp. ratio to support the cam but I would look at heads with a port volume of no larger than 170 cc.

What exactly does port volume effect?

You said your bottom end was stock. When Chevrolet built this motor, they installed the piston with a deck height of around 0.035". That means that at top dead center of any one of the pistons, the measurement from the top (or crown) of the piston to the block deck is around 35 thousandths of an inch. When we add the head gasket thickness to that figure (I'm assuming a gasket thickness of around 0.040" (40 thousandths of an inch), we get a squish figure of around 0.075" (75 thousandths of an inch). This is the distance from the crown of the piston to the underside of the head with the piston at top dead center. This distance is too wide for the piston to be able to squish (squeeze) the mixture and shoot it across the combustion chamber. When you set the squish (also called quench).......(do a search on Google to learn more)......to around 0.035" to 0.040", you minimize the distance and get the best squish, but still just barely avoid a piston/head collision due to the stretching of the crank and rods as the piston comes to the top of the bore.

Without the "jetting" of the mixture across the chamber, you can't run a compression ratio much higher than 9.0:1 on available pump gas without the motor detonating. (sounds like shaking a tin can full of marbles). That is the sound of the motor beating itself to death and it won't last long if it is detonating. If you can visualize a sledgehammer blow to the top of the piston every time the plug fires, then you can visualize what happens when the motor is detonating.

You would want to determine what compression ratio you will run first. That will be determined by the heads, piston crown configuration, deck height and gasket thickness. Once you have determined the c.r. you want to run, you want to set the squish with the gasket thickness and deck height (distance from the crown of the piston to the flat surface of the block deck). Once you have all this figured out, then you can think about ordering the cam you want to run. You see, you can't just run out and buy the cam without knowing all these other things. The cam supports the total combination of parts. You can't make a motor faster just by throwing in a lumpy cam if you don't match the cam to the c.r. If you do, you'll have a motor with a soggy bottom end that would have run better with the stock cam.

Originally posted by SBC Maro
What exactly does port volume effect?

Port volume should be based upon engine size and r.p.m.If you (over head) any engine the effect is much like (over camming) one.The end result will be poor throttle responce.

Well, to put it simply:

That is something I wished I would've found out before ordering parts. Thx to god for return policies. I got a bit excited, and put a bit too much trust into a tech advisor.

This is super valuable advice for me. Thanks alot for helping out so far.

Originally posted by SBC Maro
Well, to put it simply:

That is something I wished I would've found out before ordering parts. Thx to god for return policies. I got a bit excited, and put a bit too much trust into a tech advisor.

This is super valuable advice for me. Thanks alot for helping out so far.

I would try either a Dart Iron Eagle S/S head at 165 cc. or a World products S/R Torquer head at 170 cc.

Originally posted by SBC Maro
What exactly does port volume effect?

Port volume affects the velocity of the fuel/air mixture. A small volume figure will work great on the vast majority of OEM motors that haul grandma to the bingo hall, but when us hot rodders get hold of the motor, we want to rev the motor higher to get more horsepower out of it, so we replace the small port heads and small port intake manifolds with ones which are larger and will flow more mixture at higher rpm's. Just as with everything else in life, there is a limit to the volume which you can effectively use in a street motor. Heads with 230 cc's of volume might work great on a race motor that sees 7,500 to 8,000 rpm's, but they would be too large to maintain any sort of velocity to pack the cylinders on a motor that would only see....maybe....5,000 rpm's max. Consensus of opinion seems to dictate that somewhere between 170 and 195 cc's will be optimum for a street motor, leaning heavily toward 170 if you want to be realistic.

Cool, these are things I have always wondered about.

Good stuff, I'm making sure to take note of all this.

http://racingsecrets.com/article_racing-10.html

Good article.