Anyone use one of these? I bought one about 13 years ago for my 355. It matched the cam. The cams specs:Part#E110321 hi-flow AH 284deg adv dur,220deg @.050, .472 lift 108lsa. The cam kit is part#E811011 and the only specs are the deminsions (1.750x1.220) of the spring and I can't find anything else. Nothing is on the sheet or the manufactures sheet that i can find about the seat,open pressures, coil bind or spring rate. I want to go with a slightly larger cam. I am running S/R torquer heads w/67cc angle plug chambers 2.02 and1.6 valves, speed pro .030 cast flat tops,edelbrock performer rpm intake, shortie headers, mallory comp 9k distributor and 60kv coil. I love the sound of the cam i have but the vacuum blows and my brakes really suffer. Is it the lsa that is killing the breaks or the lift? I have a th400 long tail and don't have a stall either but will put one in. Any and all suggestions will be considered. THankS

 

I think the specs on the springs are
1.75" at 0 lift
1.22" to coil bind.
1.75-1.22 = .530" max lift, theoretically.
Pressure is probably around 100/300. Pretty standard spring.

Yea, that 108 LSA is hurting your vacuum, also the slow ramp rate - 284 is a big cam, lots of "rumpity rump" there, but 220 is fairly small, not a huge amount of power. It's overlap that kills vacuum, not lift. Maybe you want to check my camshaft article in my sig if you want more info.

I'd look at a compxe274, with some new springs, just to be safe.

274/280 - 230/236. 110LSA .500 lift, +/- .020" (the lift is something in that range, my memory is hazy)

That should give more vacuum (just a bit), and be more powerful overall. It won't be a drastic change though, if you go bigger than this, you'll have your vacuum suffer even more.

oh, a different stall speed is absolutely necessary for your current cam, and the one i'm suggesting. Probably in the 2600RPM range, but don't quote me on that.

 

1 question on that....i absolutely love the sound from that cam thru the borla 3" stainless (no cat of course with the 2" pass thru)...it sounds like the muscle of old without the glasspacks, it has the poppity sound we all love, i don't want to lose that even at the cost of vacuum...all that being said..does that change your suggestion on the cam..i have a vacuum canister ..another piece of info to consider on the brake issue, i changed the rear out to a posi disc and put a prop valve on that was for a 4wdisc car, did i miss a component in the upgrade, is the booster different or something like that?

 

Advance the cam in the motor 4 to 6deg from the cam card spec. According to the Erson catalog that cam goes in "straight up" (108LSA) . Degree it and advance it.
Further a 108LSA cam is not right for "Shorty headers" A 112-114LSA would be better overall especially thru mufflers.
But you could improve things by making a custom Y pipe using a Flowmaster Y collector #Y250350 (2.5" in 3.5" out) for a 2 into 1 exhaust.
Needs a big-big muffler too.
Again, advancing the cam 4 to 6deg will help match the cam to the exhaust better.
The headers and collector(s) have to work with the cam timing (duration and LSA) to make power.
Ultimatly, you need long tube headers.

Redo the ignition timing mechanical advance curve to allow much more inital timing at idle. You need 24+deg at idle but the same 34-36deg at max rpm. So, you have to shorten the mechanical advance travel in the distributor from about 20-24deg stock to about 10-12deg mechanical travel.
New timing will be 24deg base at idle (750rpm) and 34-36deg at max advance. 3000+ rpm.
Swapping weights and springs alone will not achieve this. you have to shorten the travel of the advance in the distributor. (advance bushing and/or weld up the slot)

These changes will maximize the idle vacuum and make the car more responsive to the throttle as well with your Erson 284* cam.
The more exhaust back pressure, the less idle vacuum you get (2" exhaust pipes are way way too small) Use 2.5" dual exhaust or 3 to 3.5" single exhaust. A 2" pipe is too restrictive.

How much manifold vacuum do you have now, at idle?
the brake booster may be faulty too.
A Erson cam cannot be directly compared to a Comp cam by looking at the "Advertized Duration" They are measured differently. Reguardless, you should be having no power brake problems with that cam. Just needs to be set up better. Its all in the details. Yes a high stall converter will help.
get a 9.5 or 10" converter, not a cheap "restalled" 12" converter. recommend a ATI converter.
http://www.atiperformanceproducts.com/
Your cr is probabily too low also. Some flat top rebuilder pistons are .045" in the hole at tdc ( typical H345P pistons) . If yours are, wack .030" off the heads and run a thin .015" shim head gasket.

 

as posted, i have a borla 3" stainless, the ones that have the interchangeable plates from a blockoff plate that sends everything thru the muffler to a 3"hole that is basically a free flow exhaust. the shorties are 4into1 with a 2.5 collector wrapped...as far as ignigtion, i have the comp9000 by mallory...can you do anything with it?

 

ttt
where can I get the .015 head gasket...summitt doesn't have or I couldn't find one. any other ideas or opinions are appreciated.

 

GM.
.015" is the factory style steel shim.

 

Are my heads worth a port and polish with unshrouding the valves. I read an old article in the chevy connection magazine that they achieved 227 @ .450 max intake (dropped to 219 @ .550) and 178 @.550 max exhaust. I don't understand why the more lift caused the flow to decrease on the intake but not the exhaust but that's irrelevant. The article didn't say how much hp was gained but stated that it was over 20 (torque not mentioned).

 

Not suprised by that flow test result. Most stock chevy heads and replacements like the SR heads reach a flow peak and actually flow less when the valve is lifted higher. This has to do with the shape if the combustion chamber around the intake valve and near (within 5/8") of the spark plug.

You can port these heads and get these results. If you want to extend the very high lift flow (higher than .500" lift) you need to rework the combustion chamber shape nar the plug and raise the intake port roof from the manifold flange right thru to the bowl area. Look at other popular cylinder heads like the vortecs and Darts and RHS lightnings to see what needs to be done. (all have heart shaped combustion chambers) All have the chamber wall layed back and radiused near the plug. You can rework you heads more like this and get high lift flow as well. The limit is the cylinder bore diameter. Do not use a typcial head gasket as a guide. it is much bigger than the bore size.

what kind of valve lift are you planning on using?
if you're sticking with the .472" lift cam then you don;t have to worry about this too much. Your heads wil still respond to a full port job reguardless. They can work vey well but need a full porting. remove a valve and look at those huge valve guide bosses in the valve bowls. Major area to rework. lots of flow and power to be had.

 

The new S/R torquers will handle .560 lift. I don't know if mine were manufactured to the same specs or not. I want to upgrade to a roller cam as this is one of the many roller blocks that came with the flat tappet cam. It is not a daily driver in the literal sense. More like a trip to the strip and every now and again in the summer i will drive it to work and show off . I was thinking a dual pattern somewhere around .510 & .535 on the exhaust. I think my exhaust would be able to let it breate enough..i think.

 

How much intake manifold vacuum do you have at idle?
Did you try reworking the distributor advance as I described?
That mallory distributor is adjustable. Needs to be set up.
Is you brake booster pooched?

 

Engine is out of the car right now..just got it back from paint. Now i gotta have surgery on my shoulder thursday so it will be awhile before i can do anything to it.....as far as the adjustability of the distributor...how other than bumping the timing up and down by rotation? It has no vacuum hose or anything of the sort. OH,don't have a vacuum gauge..gonna get one and put it on my canister..it would read about the same as if hooked up to carb wouldn't it?

 

I believe that mallory distributor is fully adjustable. It really needs to be set up to match your cam. It does not have vacuum advance at all? You can download the instructions for that model distributor from Summit or direct form Mallory (Mr. Gasket) Needs more than just moving the timing. Most of your problems are in the setup.
You need to remove it and look at how it works and read the instructions. Are you grasping the concept of my earlier posts about limiting the mechanical advance travel in the distributor that will allow more intial timing at idle but the same max advance at high rpm? I get the feeling this is going over your head. Sorry.

 

[quote=F-BIRD'88;3220169]I believe that mallory distributor is fully adjustable. It really needs to be set up to match your cam. It does not have vacuum advance at all? You can download the instructions for that model distributor from Summit or direct form Mallory (Mr. Gasket)
any ideas? http://go.mrgasket.com/pdf/Series91_93.pdf like i said, no vacuum hose hooks to t at all so do i have to go with the hyfire box or what?