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Old school Camaro question need help.

This is a discussion on Old school Camaro question need help. within the Internal Engine forums, part of the LSx Technical Help Section category; I have a 77 camaro with 10 to 1 flat tops,Vortec heads 194/155 valves,Rpm intake,750 holley 3310, small tube headers, ...

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    Question Old school Camaro question need help.

    I have a 77 camaro with 10 to 1 flat tops,Vortec heads 194/155 valves,Rpm intake,750 holley 3310, small tube headers, 280 Comp cam 480/480 with 1.6 roller rockers.I checked the compression on the engine it run from 180 to 190 per cyclinder, is this a good read or would it be low for a street and strip car? I ask because the car seem to be missing something on the bottom end,and it's not all that great on top either. What do I need to do to get some real power out of this car, with the compression I have ?

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    2 SS's are better than 1 Jays00ss's Avatar
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    first off I think you are running too big of a carb for a small block, Have you checked your plugs?

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    Senior Member Danger731's Avatar
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    Should be 210 on the read but, not bad. The 750 should be strong up top. Auto or manual ?

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    on my 74 z i have a 350 with no vortech heads the old camel humps but been ported and polished with 202 valves a 510 499 cam with 233-238 duration cam and i run a 670 carb, which when adjusted right gives all the fuel i need, its also a 4 speed so that helps a bit, same intake and rockers as you, its good for 303 to the wheels,

    i think the carb is to big, or maybe you need to look into replacing your old hei with a new one if you havent dont that yet, sometimes the ignition module or coil stops workin correctly either on primary side of ignition or secondary. check your distributor and see if you can get like a 650 double pumper maybe even a edelbrock carb, more user friendly and just a more relable carb

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    Moderator Firebirdjones's Avatar
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    Carbs not too big,,,,3310 is a vacuum secondary and they are very forgiving when it comes to size. If you bought it new and it still has stock jetting it should be close. If it was bought used it's hard telling what someone has done inside that carb. Metering blocks could have been drilled, jets changed etc....but as far as the size itself, it should work just fine. I run 750-780 carbs on 327's without issues. Tuning is a big factor.

    Also check the distributor, you didn't mention if you had a decent timing curve. Shoot for 16-18 degrees of initial timing and have about 14-16 degrees of centrifical advance for a total of around 32-34 degrees with the vacuum advance plugged off (while checking,,,if you have it). Vortec heads have pretty efficient combustion chambers and don't require alot of timing,,,32-34 degrees should just about do it,,,anymore and power will fall off.
    Make sure the advance mechanism is working properly as well,,,and have all of the curve come in by 2500 rpms or close to that,,,,this will change slightly depending on gearing, transmission,,,if automatic then a slightly more aggressive curve is necessary,,,also torque converter will play a roll,,,and how heavy the car is too. This will be something you have to play with and find a happy spot. Track testing is one of the best ways to do this.

    After timing is established,,,then I like to tackle the carburator if needed.

    The combination looks pretty mild to me,,,should make good power up to around 55-5800 rpms.

    As a general rull of of thumb,,,,190 psi of cranking compression is about the limit for pump gas,,,anymore and detination starts becoming a problem. There are other factors that come into play but would take a book to explain.
    Depending on the area where you live and what pump gas is available may give you some fits.
    Out west 91 octane is as good as it gets,,,and this would be marginal with 190 psi of cranking pressure. I have run street motors with 190-195 psi and cast iron heads on pump gas with success,,,but we have 94 octane sunoco gas where I am from.
    Your vortec heads with it's efficient combustion chambers may be your saving grace here. Just be convervative on the timing curves I listed above and sneak up on it. Like I said, the track is the best way to tell,,,keep an eye on your mph and tune accordingly. Without the car in front of me I can't be of much more help than that. Hope that gets you started,,,,Larry.

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    Senior Member Street Lethal's Avatar
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    Sounds like your carb, as well as your timing, needs a little tweaking....

    Quote Originally Posted by Street Fighter
    I have a 77 camaro with 10 to 1 flat tops,Vortec heads 194/155 valves,Rpm intake,750 holley 3310, small tube headers, 280 Comp cam 480/480 with 1.6 roller rockers.I checked the compression on the engine it run from 180 to 190 per cyclinder, is this a good read or would it be low for a street and strip car? I ask because the car seem to be missing something on the bottom end,and it's not all that great on top either. What do I need to do to get some real power out of this car, with the compression I have ?

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    Senior Member camarojunky74's Avatar
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    i would say that that carb is still to big, at least for my taste, if you have acess to a 5 gas machine you can see how shes running and make a good diagnosis of whats going on, or acess to an ignition scope that will give you the run down on your ignition system and you should be able to have it dialed in after that.

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    Quote Originally Posted by Danger731 View Post
    Should be 210 on the read but, not bad. The 750 should be strong up top. Auto or manual ?
    I have a 350 automatic by TCI. I do alot of comparing of engines and all that I have read about that have the same set up uses the 750 vac. carb.If 210 is good than I must be pretty low or just getting by.Need to abb that the 350 engine in the camaro is bored 60/.

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    Quote Originally Posted by camarojunky74 View Post
    on my 74 z i have a 350 with no vortech heads the old camel humps but been ported and polished with 202 valves a 510 499 cam with 233-238 duration cam and i run a 670 carb, which when adjusted right gives all the fuel i need, its also a 4 speed so that helps a bit, same intake and rockers as you, its good for 303 to the wheels,

    i think the carb is to big, or maybe you need to look into replacing your old hei with a new one if you havent dont that yet, sometimes the ignition module or coil stops workin correctly either on primary side of ignition or secondary. check your distributor and see if you can get like a 650 double pumper maybe even a edelbrock carb, more user friendly and just a more relable carb
    I have a brand new Accel distrbutor and I have a brand new Holley 650 DP. that did nothing for the performance, so the 650 is on the shelf, back in the box.

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    Senior Member camarojunky74's Avatar
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    i didnt say it was gonna raise his performance i simply said that it may fix his car bottom end problem and or misfires.

    and accel is shit for parts in my expereince with them, same as comp cams,
    had a lot of quaility issues with them in the past and refuse to use them.

    but thats just me

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    Quote Originally Posted by Firebirdjones View Post
    Carbs not too big,,,,3310 is a vacuum secondary and they are very forgiving when it comes to size. If you bought it new and it still has stock jetting it should be close. If it was bought used it's hard telling what someone has done inside that carb. Metering blocks could have been drilled, jets changed etc....but as far as the size itself, it should work just fine. I run 750-780 carbs on 327's without issues. Tuning is a big factor.

    Also check the distributor, you didn't mention if you had a decent timing curve. Shoot for 16-18 degrees of initial timing and have about 14-16 degrees of centrifical advance for a total of around 32-34 degrees with the vacuum advance plugged off (while checking,,,if you have it). Vortec heads have pretty efficient combustion chambers and don't require alot of timing,,,32-34 degrees should just about do it,,,anymore and power will fall off.
    Make sure the advance mechanism is working properly as well,,,and have all of the curve come in by 2500 rpms or close to that,,,,this will change slightly depending on gearing, transmission,,,if automatic then a slightly more aggressive curve is necessary,,,also torque converter will play a roll,,,and how heavy the car is too. This will be something you have to play with and find a happy spot. Track testing is one of the best ways to do this.

    After timing is established,,,then I like to tackle the carburator if needed.

    The combination looks pretty mild to me,,,should make good power up to around 55-5800 rpms.

    As a general rull of of thumb,,,,190 psi of cranking compression is about the limit for pump gas,,,anymore and detination starts becoming a problem. There are other factors that come into play but would take a book to explain.
    Depending on the area where you live and what pump gas is available may give you some fits.
    Out west 91 octane is as good as it gets,,,and this would be marginal with 190 psi of cranking pressure. I have run street motors with 190-195 psi and cast iron heads on pump gas with success,,,but we have 94 octane sunoco gas where I am from.
    Your vortec heads with it's efficient combustion chambers may be your saving grace here. Just be convervative on the timing curves I listed above and sneak up on it. Like I said, the track is the best way to tell,,,keep an eye on your mph and tune accordingly. Without the car in front of me I can't be of much more help than that. Hope that gets you started,,,,Larry.
    Carb. was bought new,so no monkey bussiness has been done to the carb.Will try what you have said and see if anything helps.Maybe I have just gotten use to the power of the car and it don't seem as fast as it use to.I run 93 octane.

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    Quote Originally Posted by Street Fighter View Post
    Carb. was bought new,so no monkey bussiness has been done to the carb.Will try what you have said and see if anything helps.Maybe I have just gotten use to the power of the car and it don't seem as fast as it use to.I run 93 octane.
    Do you have a stall and what gears are you running? I agree it sounds like a fairly mild set up I also agree it's not the carb. You could very well be getting use to the car my race car doesn't feel as fast as it use to be but the times don't lie it's just as fast as before. My friend had a 79z with a mild 350 and after a stall and 3.90s it really woke up. I think with a stall and more gear you'd get the pull you are looking for provided everything else like the timing is where it should be.

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    I have a 2500 tci stall and 342 gears With 275/60 tires. The stall was said to be the best for the setup I have. This came from Jeggs tech line.

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    This is to all that have given their thought on this question.Will better heads do anything for the car with the mile setup I have. If so what kind. I don't want to have to sale my home to pay for these heads so be reasonable.

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    Moderator Firebirdjones's Avatar
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    That doesn't sound too bad. Pretty mild stall and pretty mild gear as well. That 28 inch tall tire you are running will kill alot of that gear, but should still have plenty of butt to get you moving.

    93 octane will probably work fine on that setup with the 190 psi cranking compression you have. In my experience when you get over 200 psi or so pump gas will not get it done. It's a high octane race gas motor from there on up. But playing with camshaft numbers like overlap, duration etc....will move those cranking compression numbers around a bit.

    Sounds like you have about as mild of a cam as you can get away with,,,,with that compression ratio you say you have. 180-195 psi is a good target area for pump gas and still have a responsive motor.
    Too low of a psi number and the motor becomes lazy with no low end response,,,,but it would run on cat pee,,,lol. It's a fine line.

    Vortec heads with that mild cam and the RPM intake should make a nice package.
    Just as an example. I tuned a recent vortec headed 350 for a guy in a 79 malibu, he was running the GM hot cam,,,which is 218 and 228 at .050 with 1.5 rockers,,,,a mild cam as well in my book. RPM intake and 750 holley, 350 turbo with a very mild stall, and 3.73 gears.
    After I had the timing working right, with 34 degrees total, and actually jetted up the carb about 3 sizes, put a more aggressive pump shot in it and a larger squirter as well to get rid of a small stumble it had. This thing actually wanted more fuel.
    He made a couple of passes and it was running 13.80's at 102 mph on street tires and through the exhaust. I think the car had more in it but he didn't want to push it,,,and only shifted at 5,000 rpms. Pretty nice motor for the street that would lay some rubber and was fun to drive.

    What I am saying is,,,it's a capable package with the right tuning. Probably something simple is holding you back. A few passes at the track may tell you some things, and then you could tell if you were going backwards or forwards with future changes that you make. Cheers.

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by Street Fighter View Post
    This is to all that have given their thought on this question.Will better heads do anything for the car with the mile setup I have. If so what kind. I don't want to have to sale my home to pay for these heads so be reasonable.
    Not really,,,,,those vortec heads are about the best bang for the buck on a gen 1 small block chevy when it comes to cheap heads that work.
    They have about a 170 CC intake runner which works fine on mild 350's and promotes good throttle response and low end torque, the combustion chambers are heart shaped 64 CC that promote good swirl and are very efficient. Only thing to watch out for are the heads in stock form are only good for about .470 lift,,,anything more and retainer to valve guide clearance becomes an issue.
    Of course they can be bought from Scoggin modified in various forms for a little more money, but in basic form they are about $600 complete and are brand new,,,,thats hard to beat. I have seen many 12 second small block chevys with these heads,,,nothing to sneeze at.

    To do better you would have to step up to some decent aftermarket cast iron pieces from dart, or various aluminum heads from edelbrock, AFR, Dart, etc.....but of course the price can and will jump well over $1,000 in a hurry.
    My advice would be to stick with the Vortecs for your mild setup.
    Hell it's what GM has been using on the LT1 camaro/vette/impala motors from 92 to 97. They are the same heads only with reverse flow cooling,,,,,the combustion chambers and intake runner/exhaust runner design are all patterned from the vortec heads. LT1's were and still are great running motors in their own right,,,and alot of that is due to those heads. Just my thoughts.

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    Quote Originally Posted by Firebirdjones View Post
    Not really,,,,,those vortec heads are about the best bang for the buck on a gen 1 small block chevy when it comes to cheap heads that work.
    They have about a 170 CC intake runner which works fine on mild 350's and promotes good throttle response and low end torque, the combustion chambers are heart shaped 64 CC that promote good swirl and are very efficient. Only thing to watch out for are the heads in stock form are only good for about .470 lift,,,anything more and retainer to valve guide clearance becomes an issue.
    Of course they can be bought from Scoggin modified in various forms for a little more money, but in basic form they are about $600 complete and are brand new,,,,thats hard to beat. I have seen many 12 second small block chevys with these heads,,,nothing to sneeze at.

    To do better you would have to step up to some decent aftermarket cast iron pieces from dart, or various aluminum heads from edelbrock, AFR, Dart, etc.....but of course the price can and will jump well over $1,000 in a hurry.
    My advice would be to stick with the Vortecs for your mild setup.
    Hell it's what GM has been using on the LT1 camaro/vette/impala motors from 92 to 97. They are the same heads only with reverse flow cooling,,,,,the combustion chambers and intake runner/exhaust runner design are all patterned from the vortec heads. LT1's were and still are great running motors in their own right,,,and alot of that is due to those heads. Just my thoughts.
    the vortec heads I have came from scoggin & Dicky. They have the added lift of 525 and they were bought for a good price.I did alot of checking before I purchased them. They seem to flow as good as some of the name brand heads, so I felt that I couldn't go wrong with them.

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    Moderator Firebirdjones's Avatar
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    You are right. Great heads for the money. Been many dyno flogs with these heads on various size motors over the last few years. They always came out with good results.

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