Cascade Crew

[Quasi-Traction]

Ok So I finally got the specs for the stock LG4 and LB9 "peanut cam":

Valve Lift: intake .360
exhaust .388

Lobe Lift: intake .236
exhaust .258

Duration: intake 226º
(crank) exhaust 245º


Now with that in mind I"m considering two plans:

#1) Retain the Stock LG4 heads with minimal porting or no porting and this cam:http://store.summitracing.com/partdetail.asp?part=LUN%2D06101&N=4294908216+4294840138+4294925023+4294908198+4294887637+4294887485+4294837361+115&autoview=sku

#2) Taking the 882 casting heads I have, going having minor portation done to it and putting it on my 305 with this cam:http://store.summitracing.com/partdetail.asp?part=LUN%2D06106&N=4294925232+400421+4294924497+4294887637+4294908216+4294840138+4294887598+115&autoview=sku

The 882's are 76cc's and I think the 305 heads on my LG4 are 601's with 76cc chambers also.

I really am thinking of going with the 882's but I want to get all the expert advice/ feedback before I go for anything.

I like to have a goal and a plan before I set my sights/funds towards something.

I am also considering the second cam with the SR torquer II heads. I figure that will bump my CR up to around 9.7:1 or 10.0:1. I'm not gonna annie up for aluminum heads, just gonna go with cast iron reguarless.

[rjmcgee]

305 heads are 58cc. You can ditch the 882 idea for a 305. It would have like 6 to 1 compression.

Or, run the 882's, throw in some pop-up pistons, and a 3/4 race cam and you'll be running 10's.

[Quasi-Traction]

*nod*

so portation would definately be a good idea on the stock 305 heads?

[rjmcgee]

On a serious note, that first cam is way too small. Because of the long stroke/ small bore I would cam a 305 simular to a 350. I would still like to see someone have a set of Vortec's shaved down to 58 or 56 cc's and run something like this for a cam.This one is Comp's XE262

Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,300-5,600 RPM
Intake Duration at 050 inch Lift: 218
Exhaust Duration at 050 inch Lift: 224
Duration at 050 inch Lift: 218 int./224 exh.
Advertised Intake Duration: 262
Advertised Exhaust Duration: 270
Advertised Duration: 262 int./270 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.462 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.469 in.
Valve Lift with Factory Rocker Arm Ratio: 0.462 int./0.469 exh. lift

With just a valve spring upgrade this could be run with stock Vortec's. Add a simple carb induction and you will have a stout engine on a budget.

Just my 2 cents

[chevymad]

Keep the 305 heads. Rod's right.. that cam is tiny! 393 lift? WTF? Those are old lunati grinds i think. You want the new voodoo stuff.

Something like this

http://store.summitracing.com/partdetail.asp?part=LUN%2D60101&N=4294908216+4294924497+400421+4294887637+115&autoview=sku

That cam should be fine with those heads. Maybe put a set of Z28 springs on there too. Low budget and they'll work fine at that lift. Maybe even the next cam up too.. though summits being flaky for me tonight.

[Quasi-Traction]

*nod*

Thanks for all the information guys, I really do appreciate it.

Didn't know exactly how much lift the stock heads can handle I figured about .460" was the limit. Supposing I change to say an equivilant of stock L98 or LT1 spring/retainer/lock set, can I push the thing to .500" lift? How much of a vaccum loss/timing advance will I need at idle to keep from stalling? I'm sorry if I am asking dumb questions. I understand how most of this works, but I'm still a little unclear on how lift effects the mechanics in the cylinder head on hydraulic flat tappet cams. Do the actual lifters make contact with the lobe of the cam? I always figured mechanical lifters did and the Hydraulics just filled with oil and spin and that the oil pressure from the rotating cam forced the lifters to move before they make contact with the lobes. How far off am I?

[Twilightoptics]

Lift is based on spring height and guide height. When you run more than the .450 lift, the guide gets in the way and needs to be cut down. The spring pressures are designed to keep the lifter seated on the cam for the given profile.

[chevymad]

You have the heads off? I bought a tool for shortening valve guides.. can be used with just a drill. You're definately safe at .450 lift. I've always thought the limit was .480 cept on vortecs. At least i've never ran into a problem before. I run an xe262 in the truck and xe256(pre voodoo) in the car. Had several different sets of heads on each.

If you do have the heads off. Bring them to cows. I'll bring the guide tool home from work. We can mill the guides down. If not.. i think the tools only like $50.

Who has my spring compressor(me?? lol). I think last I knew John had it. If we do these heads we'll need it.

Both my xe cams are pretty mellow. No stalling, good brakes. Even the huge voodoo I put in my 454 isnt all that wild sounding. Something the XE and Voodoo's will do for you, is increase cylinder pressure and torque. They have small advertised duration vs 0.050 durations. This keeps the engine running more mellow for the same power. Look at specs on old grinds vs these. The advertised will be huge for the same 0.050 causing alot of driveability problems.

Lifters do rub on the cam. Flat tappet lifters run off to one side of the cam lobe. The lobe is angled slightly and so is the bottom of the lifter. The lifter then spins in its bore and "rolls" over the lobe instead of just scraping across it. Both hydros and solids work this way. Looking at the lifters you can barely tell the difference between the two. But think of a solid as a lifter shaped piece of steel, no mechanicals inside it. The hydro has a little spring loaded plunger inside that the pushrod rests on. Engine oil holds the plunger out against the pushrod taking up any slack. Some oil is allowed to leak out, so a hydro never really reaches full lift. Floating the valves with a hydro can be either not enough spring, or the lifters pumping up. This happens when there isnt enough spring pressure holding down on the plunger in the lifter. Oil fills the space and then holds the valve open. You can stop pump up by basically 0 lashing the lifters. That way there will be no space for the oil to take up, but you have to adjust the valves alot like solids to make up for wear.

[Quasi-Traction]

heads are still on it, because I"ll probably be driving it to cows. If I don't get my carburator/Distributor by Thursday, I'll probably take the heads off and pack em up with me to cows. We can cut the guides down then.