Thread: What do you guys think about this combo for my 355

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Cat piss meaning 87?

Very nice tech very through. I have a couple questions:
The block has already been decked to what degree I dont know. Do I need to take it back and have them measure and possibly cut it some more?

Also about the heads. I bought my heads already rebuilt with new crane springs. I dont know which ones they used though. Do i need to dissasemble the heads and replace them?

You said I should use a quadrajet? So I should get a square to spread bore adapter?

Finally since my heads have guide plates can i use standard stamped rocker arms. Or am I that much better off with the scorpion ones?

"Cat piss meaning 87?"

Yes.

"Very nice tech very through. I have a couple questions:
The block has already been decked to what degree I dont know. Do I need to take it back and have them measure and possibly cut it some more?"

Probably not. Install the crank on oiled bearings. Snug the main cap bolts. Install a piston/rod assembly (less rings) into #1 cylinder on oiled rod bearing inserts. Snug the rod caps down. Make sure you turn the rod so that the chamfer is next to the cheek at the counterweight. Doesn't matter whether the piston is facing front or back for this measurement. Bring the crank around so that the piston is at TDC and measure the piston deck height. I don't know if you have precision tools, but you can do this with tools as simple as a steel rule and a set of feeler gauges. Stand the rule up on edge and span across the bore about 1/4" from the edge of the bore at either the 3 O'Clock or 9 O'Clock position as you are standing at the side of the block. Insert different feeler gauge blades between the bottom edge of the rule and the piston crown until you find a blade that will just slide in there with a little resistance. That will tell you the piston deck height. Be careful that you don't push the piston down in the bore after you have it at TDC. Move the crank back and forth a little each way and check with blades until you find the least blade measurement that will fit. Having a buddy hold a long bar and socket on the slightly tightened harmonic damper retaining bolt will help keep the crank where you want it to do this operation. Once you have #1 done, write it down and remove the piston/rod assembly. Now, using the same rod/piston assembly, install them into #7, #2 and #8 and repeat the measuring operation. Now you have the piston deck height on each of the four corners of the block and will know whether or not the block is square. Report the measurements here and we'll go for there.

"Also about the heads. I bought my heads already rebuilt with new crane springs. I dont know which ones they used though. Do i need to dissasemble the heads and replace them?"

Probably not. Post the particulars on the springs here. Installed height. Seat pressure. Open pressure. Spring rate.

"You said I should use a quadrajet? So I should get a square to spread bore adapter?"

No, those never work like they should. The transition is too abrupt. Use the small square bore carb.

"Finally since my heads have guide plates can i use standard stamped rocker arms. Or am I that much better off with the scorpion ones?"

Yes, use standard stamped rockers or non-rail aftermarket roller rockers. I didn't know you had the guide plates. Disregard what I said about pinning the studs. You have screw-in studs.

Okay sounds good tech. I will get back to you when I have these measurements. I am guessing the best way to determine the spring pressure, seat pressure, etc. Is to just take them to a machine shop where they have the tools for that kinda stuff?
Also....
.....what kind of square bore carb do you reccomend?
.....I have read a few other posts by you and you always rec the Keith Black D dish pistons. Why are you so fond of these? Just my own curiosities.
.....Is it considerably better to use roller rockers as opposed to the stamped variety?

Originally Posted by LURCHBIOTCH

Okay sounds good tech. I will get back to you when I have these measurements. I am guessing the best way to determine the spring pressure, seat pressure, etc. Is to just take them to a machine shop where they have the tools for that kinda stuff?
Also....
.....what kind of square bore carb do you reccomend?
.....I have read a few other posts by you and you always rec the Keith Black D dish pistons. Why are you so fond of these? Just my own curiosities.
.....Is it considerably better to use roller rockers as opposed to the stamped variety?

If you don't have the part number of the springs so that you can find the specs on them, remove one only and take it to a reliable engine builder in your area to be checked out on his spring tester. Comp specs the springs for this cam to measure 105 lbs at the installed height of 1.700" and 273 lbs at 1.250".

Square bore equals Edelbrock, Carter AFB, Holley, Barry Grant, etc.

I like the KB's because they are a premium quality piston and utilize a large flat area on the crown to mate up against the bottom of the cylinder head to produce an excellent squish of the air/fuel mixture toward the spark plug as the piston approaches top dead center. Check the large flat area on these pistons as a result of the offset D dishes as compared to other pistons that utilize a concentric dish. No comparison.

Roller tips on these aftermarket rockers are too small to generate a mechanical couple on the valve tip and have been shown to skid across the tip under high speed photography. Where these things shine is the needle bearing trunnion. That's where you are going to reduce friction to free up a little free horsepower and lower engine oil temperatures. In my opinion, Harland Sharp makes the best ones. Some of the first ones (Crane, etc.) were designed with the wrong geometry, but I'm told that HS has corrected this error. A line drawn through the pushrod axis and a line drawn through the rocker pushrod tip/trunnion should ideally be at 90 degrees to each other with the valve at half lift. Additionally, a line drawn through the rocker trunnion to the bottom of the rocker roller where it contacts the valve stem tip and the valve stem axis should be at 90 degrees to each other with the valve at half lift.

It has been said by some respected engine builders that you can pick up 20 hp in addition to lower oil temps with roller rockers (roller bearing trunnions).