Small Block & Big Block Chevy Specific - No bottom!

Okay i just installed a brand new erson 472 lift cam and a torker 2 manifold and i have no bottom end what so ever i thought that with a mild cam like that i should retain some bottom end this thing wont hardly idle with stock converter! Its in a 355 with 8:1 compression. Iam also running this with a 600 cfm edelbrock so that could be the culprit. Any help to this newb is greatly appreciated!

Well I don't know the culprit of your problem here, but what heads are you running?
The carb may be a little small, depending on the rest of your combo. Also, why the low compression? Are you planning on some boost? :nod:

Nope no boost but i change of heads is in the picture not shure which ones prolly some World products sr torqers, iam running stock heads right now. I would like to run a turbo but i dont have that kinda cash especially since i could be starting school fer long.

I would definetly grab a set of edelbrocks..I think they are the best bang for the buck..and you need a converter..your pretty much strangling your car with no converter and a mild cam like that,especially with a 600 carb on it...grab a 750 Quick fuel..

Well, an economical fix will be to get rid of the T2 intake, get a hi-rise dual plane.

Then you will need a 2200-2800 stall converter, as well as a gear.

The proper fix will be to put some compression in the motor, and a set of decent heads. But I know how it is being money limited.

If that cam is too aggressive, it won't work well at all with 8.0:1 compression. Get some more specs on the cam and post them. With compression that low, the engine needs a very short duration camshaft to keep the cylinder pressure high. An Aggressive cam bleeds off pressure..pressure that isn't all that high to begin with in this situation.

A Torker Intake is a low rise single plane if I remember correctly. It's not known for making good torque numbers at low RPM. A Simple Edelbrock Performer Intake along with that 600cfm carb should be very tame and torquey. In no way is a 600cfm carb "killing" a mild engine like this.

I'd get a compression tester and see what the cranking compression is. Something in the 160-200psi range would be "normal". The lower it gets the worse it runs, though I'm not saying the higher the better either. :guns:

Your compression ratio is what is killing your bottom end power. Until you raise the comp ratio the other variables aren't really hurting you. If you only bump the comp ratio up to 9:1 you would notice a huge difference. Start with raising your comp ratio and you will notice big changes.

I know i need a converter for shure. A coworker told me he would give me a set of 305 heads as a quick fix until i get some money prolly next year.He also said he might have a edelbrock poorformer he also thought the manifold was the problem said he might trade. My gears are 4.10's. And iam looking at a 750 right know(maybe not now), iam also now thinking about taking this out of this heavy 3/4 ton and throwing it in my 73 1/2 ton i dunno. Been out of this racing realm for long time thanks to drugs so i have alot to relearn.Thanks for the help.

Cam Specs:

Erson Prt. # E110421

Lift Duration
Intake .472 256
Exhaust .472 256

these guys are right on,that cam is not too crazy, i agree it wants some more compression, and def switch to a dual plane intake,performer RPM etc.stck with the 600 carb for now.,if its in a heavy 3/4 ton truck its gonna feel even worse,even with 4.10's
good luck

its def the compression, 8:1 is killin ya.

The truck came factory with 4.10 cogs. Ok ill look for heads and a manifold today. Thanks for teh help!

Well one of the 305 heads was cracked, had them hot tanked and magnafluxed, might have a performer rpm got to call the guy tomorrow. Cant find any matching heads at any local junk yards, besides that i have know found out that its cheaper just to buy aftermarket cuz your going to spend that muc anyway in the machine shop on stock ones. Iam shure you all already knew this.

Well almost everything mentioned so far is credible, but I would throw something else in. If it is running as bad as you make it sound, you may want to pull the timing cover and double check your alignment marks. If you used a multiple key way timing set, it is very easy to lign up with the wrong mark, and in some cases it will seem to run fine, but makes no power.

Well, if those duration #s are at 50, then that is a ton of duration for a 472 cam, I like big lift with minimum dur. in a lo compression motor.

That cam was designed for situations like limited circle track classes, where you need that dur. at higher rpms.

If cash is limited, I would advise this. Spend your money on a new intake and a new cam and lifters. You can make acceptable power at 8 to 1.

Look at cams with lift in the 450-460 range, and keep your duration around 220-230 @ 050. You must allow the valves to stay closed long enuf to build cylinder pressure.

I would also buy a Timing Set with the 3 keyway crank gear, and be sure to advance the cam, or choose the advance slot. This will encourage torque output in the lower rpm range.

220-230 is a lot of duration for low copmpression and stock heads IMO. I would probably stick around 210 range unless you are bumping compression to 9.5-1 or better. I do think that 220-230 is a good street cam with some other improvements. As far as heads, maybe some vortecs on a budget. If you want to spend some cash you can hold out for some AFR 195's. They are some of the best flowing street heads out there, and cant be beat for the money. Vortecs, Comp XE268 or 274, RPM air gap, small stall, you will be happy.

Compression is the problem, that should be at 9:1 at least for that cam.

256 duration I'd more than bet is NOT at .050". It's advertized which puts that camshaft in the VERY mild range so that's not the problem. The Intake and compression are still the worst of the combo.

Vortec truck heads like these guys are screaming about will be great but require a compatible intake. A good place to look is at www.sdpc2000.com
They can set you up with the correct top end package. Heads/Intake/Gaskets/Bolts..

A head change would probably build up his compresion since he probably has stock smog heads with 76cc chambers. 305 heads would be a quick fix for compression, but not if they will need some work. If an intake is gonna be needed anyway, Vortecs arent a bad idea. A intake for them is about the same price as any small block. Deffinetly check Scoggin Dickey for Vortec stuff.

Ive been checking out theyre vortec packages but i found some canfeilds on ebay for 500 or so right now the bid might go up kinda scared to buy used heads lol. Atleast my coworker didnt charge me for the 305 heads after i found out one of them were bad. I messed with the carburator and timing today pulls real nice from 2-6000 rpms very nice when i get out on the highway cuz iam running like 3100 to do 70 mph before it lacked alot with the stock cam know it has power which is what i wanted but i lost my bottom end but iam getting used to it lol. What size exhuast should i run iam running 2 1/2 with 40 series flows turn downs sounds good just though about running a bullet muffler lol i cant get no tickets for 60 days.Yes it did have smog but it has been smoged out with a few wrenches and headers. The cam has 228 @ 50 duration. What stall converter should i run? Well the new timing chain that i picked up had no mark on the crank gear so i just pointed the dot on the cam sprocket strait down,i ve dun three other cam swaps with succes in sbc but its been awhile. I just gave that comp ratio as a base becuase the engine was not built under my authority and i have no idea but the engine was rebuilt relativaly close to stock wich usually range from 8 to 9(i think).

How would i go about advancing the cam with a three keyed crank gear? If i did that and change the manifold with this cam still in would it bring the bottom in back up.

Ive been checking out theyre vortec packages but i found some canfeilds on ebay for 500 or so right now the bid might go up kinda scared to buy used heads lol. Atleast my coworker didnt charge me for the 305 heads after i found out one of them were bad. I messed with the carburator and timing today pulls real nice from 2-6000 rpms very nice when i get out on the highway cuz iam running like 3100 to do 70 mph before it lacked alot with the stock cam know it has power which is what i wanted but i lost my bottom end but iam getting used to it lol. What size exhuast should i run iam running 2 1/2 with 40 series flows turn downs sounds good just though about running a bullet muffler lol i cant get no tickets for 60 days.Yes it did have smog but it has been smoged out with a few wrenches and headers. The cam has 228 @ 50 duration. What stall converter should i run? Well the new timing chain that i picked up had no mark on the crank gear so i just pointed the dot on the cam sprocket strait down,i ve dun three other cam swaps with succes in sbc but its been awhile. I just gave that comp ratio as a base becuase the engine was not built under my authority and i have no idea but the engine was rebuilt relativaly close to stock wich usually range from 8 to 9(i think).

How would i go about advancing the cam with a three keyed crank gear? If i did that and change the manifold with this cam still in would it bring the bottom in back up.
The crank gear has to have a mark on it. If it does not, you may have it on backwards (mark towards the crank so you can not see it). If that is not the case, return it, it is defective. The only way you will be able to know if you have the cam installed correctly with out a mark would be to have it degreed (in fact even with a mark you can usually find it off some but at least it is in the ball park). In the case of a multiple key way crank gear you should have 2 sets of marks for each key way. One denotes which key way to use, and the other which will be a duplicate of the one next to the key, will be the one you line up with the mark on the crank gear. Just FYI, the mark on the cam gear does not line up with the keyway either. I guess if you had to you couls use the stock crank gear and line it up with the key way on the new one and make a mark where the stock one mark is, that would be much beter than just guessing. Have you checked your cranking compression yet. I am not an expert, but I would think it would be around 130-150 psi (+/-) with that compression and cam. If it is a lot higher (like 180+) or a lot lower (110-) then I would seriously consider pulling the timing cover and rechecking your cam timing, because I would almost bet your timing is off.

Nope i havent checked the compression bcuz i dont have a compression tester i will buy one soon hopefully next payday, i also have some speeding tickets to pay :(. I did not have a mark on either side but when i pulled the stock cam i had it at tdc, and thats the way everything went back together, ive dun it like this before without degreeing it and had no problems but now that i know this a degree wheel is in the works.It takes time when you dont have a dime. :usa:

I agree the low compression is killing some power. How much did you preload the lifters? Having them too tight will kill power especially low end, about 1/8 to 1/4 is plenty. Also might check your initial timing in relation to your total. You don't have stock valve springs do you? I don't think the carb and intake are killing you though. What kind of rockers do you have?

Thanks for all the info, my boss let me use the work truck to pick up my other truck and i picked up a 750 in place of the edelbrock that was on that motor. I went thru it and put it on this motor now a can spin the tires from a dead which is nice really brought the bottom end back up, what power valve should i run i put a 5.5 should i just plug it off. Iam not going to have the cash to buy a compresion tester this check have to wait another 2 weeks. Even without a mark anyone would know that it should on a stock motor alteast point strait down atleast on the cam gear with the motor at tdc on #1.

That sounds kind of strange: it picked up bottom-end power with a bigger carb.
Perhaps it was a vacuum leak?

It maybe that the holley just outperforms the edelbrock i know alot of people i have talk to say the edelbrocks are more streetable but u loose time at the track so i dunno runs alot better and power brakes seem to have more vacum to work with also.