Cam Choices

OK, I am soon to be getting a 94 Gmc Short wide truck that originally has a 4.3l V6 engine in it, I am also getting a used 4 bolt main 350 engine from a friend for free, so I am going to build the V8 in advance for when I decide to do the swap, the truck is TBI right now, but I plan to just use the stock electric fuel pump an run a return style regulator, probably a mallory, and carburate the engine so I wont have to deal with the electronics of a tbi, my question is to what cam I should use, I will drive the truck to and from work mainly but I still want it to have lots of power if I decide to hit the gas, or maybe take it to the track every once in a while to show the punks in town that it does have power to go along with the sound.
The engine I ill be getting is a 4 bolt main 350 from a 88 suburban, I will be using a brand new cast crank (don't see the use for a forged one unless I build a massive motor) and the stock rods, (may decide to upgrade to a set of eagles) with a set of ported, polished, and gasket matched 993 casting heads with the stock 1.94 and 1.5 valves, the heads will have a 5 angle valve job and aftermarket valves and springs, I will also be running flat top forged power pistons because the heads are 76 cc's, the heads will be flat milled an additional .020 thousandths for a little more compression, I will also be ordering a performer rpm or a torker II intake with an edelbrock thunder series carb, (or what ever intake you reccommend) the exhaust will be a set of equal length hedman headers with a set of flowmasters or dynamax mufflers dumped befpre the axle, and a 373 posi rear and an overdrive tranny, the camshafts I have decided to pick from are,
1. Lunati Voodoo Camshaft part #LUN-60103, 268-276 duration, .489-.504 lift, 110 lsa, 1800 to 6200 rpm's
2. Comp Cams Magnum Cam part #CCA-12-326-4, 286-286 duration, .490-.490 lift, 110 lsa, 2200 to 6200 rpm's
3. Lunati Street Master with 285-285 duration, .507-.507 lift (but on a 108 lsa)
4. Comp Cams XE part #CCA-12-246-3, 274-286 duration, .487-.490 lift on a 110 lsa.
Which camshaft would you recommend, I want the one that will make the most low end torque and use a low stall, don't want to have to run a stall above 2600 rpms, also what intake would you go with it, and how much stall do you think I will need for the cam?? I personally like the voodoo camshaft and the street master cam, but not sure about the 108 lsa, never had a cam with a 108 lsa.
Do yoe think my enine will make decent power and torque or would you reccommend I take another route?
Thanks for your help

Thought about using a hydraulic street roller camshaft ?

What are the specs on the heads ? You are really trying to make torque ,right? If you have the cash get a forged crank and some good rods.You can add some nitrous later , a little nitrous is always fun.You can run a little on cast parts though ,I think like 75 to 125 horses.

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Originally Posted by dcurtis

OK, I am soon to be getting a 94 Gmc Short wide truck that originally has a 4.3l V6 engine in it, I am also getting a used 4 bolt main 350 engine from a friend for free, so I am going to build the V8 in advance for when I decide to do the swap, the truck is TBI right now, but I plan to just use the stock electric fuel pump an run a return style regulator, probably a mallory, and carburate the engine so I wont have to deal with the electronics of a tbi, my question is to what cam I should use, I will drive the truck to and from work mainly but I still want it to have lots of power if I decide to hit the gas, or maybe take it to the track every once in a while to show the punks in town that it does have power to go along with the sound.
The engine I ill be getting is a 4 bolt main 350 from a 88 suburban, I will be using a brand new cast crank (don't see the use for a forged one unless I build a massive motor) and the stock rods, (may decide to upgrade to a set of eagles) with a set of ported, polished, and gasket matched 993 casting heads with the stock 1.94 and 1.5 valves, the heads will have a 5 angle valve job and aftermarket valves and springs, I will also be running flat top forged power pistons because the heads are 76 cc's, the heads will be flat milled an additional .020 thousandths for a little more compression, I will also be ordering a performer rpm or a torker II intake with an edelbrock thunder series carb, (or what ever intake you reccommend) the exhaust will be a set of equal length hedman headers with a set of flowmasters or dynamax mufflers dumped befpre the axle, and a 373 posi rear and an overdrive tranny, the camshafts I have decided to pick from are,
1. Lunati Voodoo Camshaft part #LUN-60103, 268-276 duration, .489-.504 lift, 110 lsa, 1800 to 6200 rpm's
2. Comp Cams Magnum Cam part #CCA-12-326-4, 286-286 duration, .490-.490 lift, 110 lsa, 2200 to 6200 rpm's
3. Lunati Street Master with 285-285 duration, .507-.507 lift (but on a 108 lsa)
4. Comp Cams XE part #CCA-12-246-3, 274-286 duration, .487-.490 lift on a 110 lsa.
Which camshaft would you recommend, I want the one that will make the most low end torque and use a low stall, don't want to have to run a stall above 2600 rpms, also what intake would you go with it, and how much stall do you think I will need for the cam?? I personally like the voodoo camshaft and the street master cam, but not sure about the 108 lsa, never had a cam with a 108 lsa.
Do yoe think my enine will make decent power and torque or would you reccommend I take another route?
Thanks for your help

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Why not build a 383??
This is a truck and you need the extra torque to get it to move.
I.M.O.,each cam you have picked is to big.
If you are building a 350 I would look at cams that have about 215@ .050.
If you are going to build a 383 then I would look at cams that have 215 to 220 @ .050.
I would either run a Performer intake with a carb. of less than 600 cfm.
Just to help get the truck to move I would run a 2,000 stall.

dcurtis, I don't mean to sound like I'm scolding you, but if you've paid ANY attention at all to the posts on this forum for the last several years, you must have learned by now that the cam MUST.....MUST be matched to the static compression ratio. If you're going to achieve success in an engine build, you can't just go picking a cam out of thin air and expect it to work for you.

The motor you're planning to screw together will have a static compression ratio of about 9.16:1 if you assume a 0.030" overbore, 76 cc heads, 5 cc's of eyebrow in the pistons and 8 cc's in the gasket (0.039" to 0.041" compressed with a zero deck). If you're planning something different from these specs, post it here so we can zero this motor in for you. I would also resist cutting the heads for more compression, 9.16 will make a great street motor with the right cam and you want all the meat on the heads you can get to insure they will seal properly. A light clean-up cut would be ok in my opinion.

If I were building your motor, here is the cam I'd choose for it....
http://www.cranecams.com/?show=brows...tType=camshaft

Do you think I could get away with the 76cc heads and one of the cams I have picked out, if I get some dome pistons? Or I also have a set of 601 casting 305 h.o. heads with 1.94 and 1.5 valves and set up for a max lift of about .510, they are also port and polished with a gasket match on the runners, with smoothed combustion chambers, not real sure on the heads cc's though, some places say 60, 58, and 53cc's so I'm not real sure, just have to measure them I guess. I built a 350 about 2 years ago with a the same 305 ho heads and same mods to them, I used stock type dished pistons,stock crank and rods, with a performer 600cfm carb, a performer intake, and a comp cams 270H camshaft, everyone at the shop told me the engine would not run due to the 10.3 to 1 compresion and that they would fall on there face at about 4500 rpm's, anyhow the engine did run and it ran very very well, it was in a 86 silverado with a 700r4 trans, with a 2000 stall and 373 gears, it would ping if I got on it with regular pump gas but if I backed off the timing it would run fine, it would run great on the 93 octane pump gas though, it also didn't stop pulling until about 5900 rpm's, it would smoke the tires from a dead stop all the way to third gear also.

P.S. The cam I chose is ground on 110* lobe centers. If you want a little more lope to the cam, call up Crane and have them grind it for you on 106* centers but retaining the 30* ABDC intake closing point. You'll give up some manifold vacuum, but hey, there's no free lunch. You have to give up something to get something.

That cam is too small thanks for the thought though, it just looks like a stock 350 cam with a little more duration and a tighter lsa, wanting a cam that will make good power to about 6200 rpm's and work with a 24-2600rpm stall.

O.K., then you'll need more static compression ratio. I would resist the temptation to do it with domed pistons though. The dome gets in the way of the flame kernel as it is travelling across the chamber. Do it with flat-tops and a smaller chamber.

The motor you were describing ran good because you had optimized the DYNAMIC compression ratio with high static compression ratio and a relatively short cam with an early intake closing point.

I think the only way you're going to be able to do what you want to is with 64 cc chambers or use the 56 cc heads with a dished piston. With 64 cc heads and flat-tops, you'd be at 10.44:1 and could run pump gas with the tight 0.040" squish and a cam such as this.....(112 LSA)
http://www.cranecams.com/?show=brows...tType=camshaft

I wouldn't run anything bigger than Comp's XE262H cam. I am personally running the Comp XE256H grind in my truck and run 15.3's in the 1/4 with 3.07 gears and a 29.6" tall tire. The truck is so overgeared, I cross the 1/4 mile in 2nd gear and still have rpms to go. With new gears, the truck would probably do mid-14's. In a vehicle that heavy, you need torque. Run the smaller cam. My 350 will run 5500 rpm with the cam it has. That cams you are looking at are built to run 6500 rpm. If you go much over 5000 rpm on a worn out, stock bottom end, you will be spitting rods out and breaking piston rings in short order.

The bottom end isn't worn out, if you would read correctly you would see that I have a brand new cast crank, and may upgrade to a set of eagle rods with power forged pistons, which I ordered yesterday. I'm leaning towards either the XE 274 ot the Lunati Voodoo cam, Tech as it happens I do have a set of heads in my garage that are 64 cc's, I will get the numbers for you today and see if you think those would be ok with a valve job and a good port, polish. I acually have 4 or 5 differant sets of heads but only one set is a small chamber set, the others are 400 heads and the 993's.
If I get to the correct compresion, which cam do you think will pull the hardest, the voodoo or the comp xe, sorry for being stuck on those 2 cam choices, but I guess I am har headed, but I am willing to do whatever I need for the engine to operate correctly with one of the 2 cams, gonna have about 3 or 4 months to finish the engine, so I'm not in a hurry, and I'm sure I'll learn a lot more in that time. Thanks

The heads I haave turn out to be 14102187 heads which I believe are 305, 87-91, 1.85-1.5 valves, 58 cc's, 7 bolt ex, prolly swirl port tbi, so prolly wont use.

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Originally Posted by techinspector1

O.K., then you'll need more static compression ratio. I would resist the temptation to do it with domed pistons though. The dome gets in the way of the flame kernel as it is travelling across the chamber. Do it with flat-tops and a smaller chamber.

The motor you were describing ran good because you had optimized the DYNAMIC compression ratio with high static compression ratio and a relatively short cam with an early intake closing point.

I think the only way you're going to be able to do what you want to is with 64 cc chambers or use the 56 cc heads with a dished piston. With 64 cc heads and flat-tops, you'd be at 10.44:1 and could run pump gas with the tight 0.040" squish and a cam such as this.....(112 LSA)
http://www.cranecams.com/?show=brows...tType=camshaft

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Oh,come on Richard you sound like a "broken record" now.:LOL:

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Originally Posted by erik erikson

Oh,come on Richard you sound like a "broken record" now.:LOL:

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Erik, coming from you, I'll take that as a compliment :)
You may have noticed that I don't respond to every thread, because my area of expertise is limited to certain areas of car building, but I'm pretty sure that engine combinations is one of those areas.
You know that I value your knowledge and opinion, do you agree that I'm giving the correct advice in this instance, or is there something different that you would advise?

dcurtis, here's your homework assignment. Call the cam grinders of the cams you have chosen and get me the intake closing point @ 0.050" tappet lift. Let's try to get this right the first time so you're happy with the outcome.

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Originally Posted by techinspector1

dcurtis, here's your homework assignment. Call the cam grinders of the cams you have chosen and get me the intake closing point @ 0.050" tappet lift. Let's try to get this right the first time so you're happy with the outcome.

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The xtreme energy 274 has intake open @9, intake close @41, and the exhaust open @52, and close @4.
will get the other cam in a minute.

Just tried to call the lunati phone numbers on holley's website and none of the numbers will work. So I will have to find them some other way.

Just found a 350 build that used the voodoo cam and it made 437 ft.lbs tq at4200rpm's and made 411 hp at 5800 rpm's, they had 9.6 to 1 compression, a crosswind intake and a 750 holley, also ran a 2400 stall.

I think since I have lots of time to finish the engine I will just save my money for a while and get some world products or some dart iron eagle heads, or whatever manufacture has a descent set of heads at a descent price, don't want to go over $800.00 for a set, and will probably get some with between 170cc and 180cc runners, still need cam help but another question is, if I run a set of 4 valve relief flat tops, what chamber size would I need to get around 10 to 1 compression, because thats about where I want to be compression wise, where would 64cc or 67cc chambers get me with a standard deck 350 and a .040 thick gasket?

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Originally Posted by techinspector1

Erik, coming from you, I'll take that as a compliment :)
You may have noticed that I don't respond to every thread, because my area of expertise is limited to certain areas of car building, but I'm pretty sure that engine combinations is one of those areas.
You know that I value your knowledge and opinion, do you agree that I'm giving the correct advice in this instance, or is there something different that you would advise?

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We where only five degree's different on our cam recommendations.
I would recommend that he favors the exhaust by 6-8 degree's.

Here's the calculator for KB pistons that I have used many times to get close on a combination.....
http://kb-silvolite.com/calc.php?action=comp

Use the following values:
Cylinder head volume 67
Piston head volume 5
Gasket thickness 0.039
Gasket bore 4.100
Cylinder bore diameter 4.03
Deck clearance 0
Stroke 3.48
Rod length 5.7
Intake closing point 56 (the calculator uses the actual intake closing point @0.050" tappet lift plus 15 degrees, so add 15 to 41 on the Comp 274 cam and you enter 56 into the calculator. When I first began using this calculator, we settled on 8.00 to 8.25 to 1 DYNAMIC compression ratio as a figure to attain for pump gas. Since then, I have been advised that these figures are valid, but that the KB calculator is a little on the conservative side. So, I think if we shoot for 8.4 to 8.5, we'd be a little closer to reality with this particular calculator.

Plugging in the values, we get 10.046 static compression ratio and 8.536 dynamic compression ratio. This is using 67 cc heads, flat-top pistons with 5 cc's of valve relief, zero deck (piston crown even with the deck at TDC) and a Fel-Pro 1074 or similar gasket that compresses to 0.039".

You can play with the calculator and enter different values to find the results, but I would shoot for somewhere between 8.4 and 8.5 dynamic compression ratio no matter what combination you use.

The other thing I would advise is to shoot for 0.035" to 0.040" squish. I have shown this build with zero deck and a 0.039" gasket for a squish of 0.039". You can achieve the same results by juggling the deck and gasket thickness. For instance, you could have a deck height of 0.024" and a gasket of 0.016" for a squish of 0.040". Or you could have a deck height of 0.012" and a gasket thickness of 0.028" for a squish of 0.040" It doesn't matter how you get there, as long as you get there. Without this tight squish, you'll never get the motor to operate properly on pump gas.