350 roller build

[makoshark]

I have been restoring my car since before Rip Van Winkle went to sleep! and have finally gotten to the motor build. I originally was going to build a 383 and had bought a few parts for that build through the years, but obtained a fully forged 0 mile LT1 not long ago. I had some doubts about the LT1 build for reasons and tore the motor down to find the cylinder bores were honed with a drill. So I took the Eagle 4340 crank, Eagle H-beam rods, Ross 4.003 forged pistons, LS7 lifters, 1.6 Comp roller rockers, Comp push rods, Bullit Racing Cams custom hot cam and bought a new 350 roller block.



Here`s the details of what I`m going to build with those parts. I have an Edelbrock Performer RPM intake and Speed Demon 650 DP carb, thinking about buying the MSD E-Curve distributor. Thoughts on dizzy? I need heads! I have a set of 70`s 624 smog heads that I am forced to use for the time being. I have some stainless undercut 2.02 and 1.6 valves, Comp 986 springs and Comp titanium retainers already. I simply can`t afford to buy heads right now. Money is that tight. Ross lists the pistons with 8.8 compression with 76 CC heads. The heads I have are 76 CC heads. What compression do I need to shoot for to keep it running on pump gas and how do I need to obtain it?

Also, the pistons are 4.003, not 4.030. Is that standard bore with a hone?

Specs on cam:

duration at .050...218 intake and 226 exhaust
lobe lift.....3200 and .3200
separation....111
timing events .050 2op-36cl and 48op and -2cl
duration at .006 284 and 292 exhaust
gross lift .522 and .522 with 1.6 rockers
degree intake lobe to 107

Cam was specifically ground with 1.6 rocker ratio added in the equation

[another69]

I know money's tight, but those heads are gonna kill power potential. Look around for a set of used heads, maybe even vortecs. SBC stuff is very cheap & plentiful. If you've waited this long, maybe you can wait a little longer.

Your cam is kinda mild, but it will probably highlight even more how bad the heads are. If you are dead set on keeping those heads and that compression, you need to match it with a smaller cam. There's no point on going past .500 lift if the heads stall at .400 or less.

I'd shoot for 10:1 comp, and get another set of heads

[makoshark]

I never said I wanted 8.8 compression. I was stating Ross lists the pistons I have at that compression with 76 CC heads. I know the heads are not great, but money is too tight to spring for heads right now. Vortecs are completely out of the question. I will not run those. What I want to know is what compression can I safely get to on pump gas with these iron heads and how should I go about it. Also, does 4.000 bore + hone = 4.003?

[another69]

Not sure about the bore- I'd ask Ross.
Why are Vortecs out of the question?
If your pistons with a 76cc chamber= 8.8:1, how can you gain compression? (it sounds like you already have the pistons) You can only go so thin with a head gasket, and you need to have the piston very close to deck height, but you still need clearance to keep the piston from contacting the head when things grow as RPM and temp rises.

You need to mock up the pistons on the rod & crank after the block has been machined, and measure piston to deck height. Add piston dish and valve reliefs. Then add gasket thickness and chamber cc to figure out rough compression. (alot of helpful calculators online) Compression, heads, and cam are very closly related, so what are you willing to change?

If you want higher compression, you may need a dome piston, which is not really ideal. With those heads, you could probably safely go 9.5:1, maybe more, but you may as well stick with 8.8:1

[makoshark]

If I used vortecs, then I`d have to buy a new intake. I listed all the parts I already have in my original post. Yes, I already have, crank, rods, pistons, brand new block, performer rpm intake, speed demon 650 dp, cam, lifters, valves, springs, titanium retainers. I received the rotating assembly in a trade. it`s brand new stuff all forged.

Heads can be milled and thinner head gasket will bump up compression. I can do a home port on the heads. That`s not outside of my capabilities. If I bought vortecs and new intake, I could buy RHS iron heads for that price and add all my valvetrain parts. The heads are not a permanent item. Just to get it running and going and possibly AFR`s down the road. Trying to get this car back together and going and work out some of the kinks, such as heads later.

[another69]

Ok- well if you want to use what you have and upgrade later, then spend your time on the shortblock. Try to get the piston very close to being flush with the deck, within .010 or less. This will help with quench later when you get good heads. This will mean your head gasket needs to be no thinner than .045 to prevent contact. (0 deck) The heads are probably open chamber, right? If so, don't bother wasting time with them. Put them on as is, don't even port them. Milling or porting will not be worth it for the small gain you may (or may not) see. Get a set of 64cc heads later (you have 2 valve relief flattops, right?) but don't spend another dime or minute on those heads- besides springs, which you did already.

Actually measure your compression and valve- piston clearence, and coil bind-they are easy steps that should not be skipped. If you really have 8.8:1, at least you could run on 87 pump gas. BTW- what is the car weight and gearing and trans that this is going into?