'81 Vette: Car's too fast!!

[k belknap]

I just purchased an '81 Vette which someone has obviously "hot-rodded". The body and interior are in pretty good shape and are 100% original. However, the engine concerns me. It idles at about 700 RPM and you pretty much have to give it just the teensiest bit of gas to keep it from really shaking. Evidently the cam has a 10 million duration (a little exaggeration). My questions are: a) Is there a manual/website which could walk me through restoring an engine to it's factory specs... b) Could I buy a crated engine and how much would it cost... and c) Could I possibly just change out the cam to "calm" the engine down a little?

Thanks for your help!

Kevin

[George Daina]

Maybe all you have to do is....

change the cam, but best, if you can, track down the original owner and find out what modifications were done to the motor. If not, then a tear down might be in order and replace non stock items w/stock items.

If this was my car, I'd count my blessings and drive stop light to stop light with a grin on my face.

[George Daina]

Maybe all you have to do is....

change the cam, but best, if you can, track down the original owner and find out what modifications were done to the motor. If not, then a tear down might be in order and replace non stock items w/stock items.

If this was my car, I'd count my blessings and drive stop light to stop light with a grin on my face.

[Jim]

Re: '81 Vette: Car's too fast!!

I'm not sure what your biggest concern is. Is it the "shaking" or are you just in search of a stock original car? If you want a stock original car, then most likely an entire rebuild with stock parts will be necessary (do you even have the original block?). If you just want to mellow the engine, then you can change the cam, but first make sure the set-up is OK (ie timing, ignition, parts, etc.) For example, if the cam is radical and you have a fairly high compression ratio, an MSD set-up will help smooth it. If the carb has a problem, this could also cause the problem you are experiencing. The car may also be over-carbed, I am not familiar with the whole set-up, but for street use I highly doubt this car needs more than a Holley 650 double pumper. These are a few examples but even a hot street motor should not shake is it's is set-up right. Just because someone hot-rodded a motor, it does not meant that the person knows how. If you want a quick fix to the shaking, just turn up the idle a little more. Good Luck, Jim - Elkhart '73

[Jim]

Re: '81 Vette: Car's too fast!!

I'm not sure what your biggest concern is. Is it the "shaking" or are you just in search of a stock original car? If you want a stock original car, then most likely an entire rebuild with stock parts will be necessary (do you even have the original block?). If you just want to mellow the engine, then you can change the cam, but first make sure the set-up is OK (ie timing, ignition, parts, etc.) For example, if the cam is radical and you have a fairly high compression ratio, an MSD set-up will help smooth it. If the carb has a problem, this could also cause the problem you are experiencing. The car may also be over-carbed, I am not familiar with the whole set-up, but for street use I highly doubt this car needs more than a Holley 650 double pumper. These are a few examples but even a hot street motor should not shake is it's is set-up right. Just because someone hot-rodded a motor, it does not meant that the person knows how. If you want a quick fix to the shaking, just turn up the idle a little more. Good Luck, Jim - Elkhart '73

[k belknap]

Re: '81 Vette: Car's too fast!!

Hi Jim! My main concern is returning the car to it's original state (as much as possible). The "shaking" is a result of the cam. I've had a couple of street-rod freaks drive it and they absolutely love it. However, it's not my cup of tea. I would prefer to just change out the cam and possibly the carb. In case of a total rebuild with stock parts...how much $ am I looking at? (I guess that's always the biggest concern).

Thanks,

Kevin

[k belknap]

Re: '81 Vette: Car's too fast!!

Hi Jim! My main concern is returning the car to it's original state (as much as possible). The "shaking" is a result of the cam. I've had a couple of street-rod freaks drive it and they absolutely love it. However, it's not my cup of tea. I would prefer to just change out the cam and possibly the carb. In case of a total rebuild with stock parts...how much $ am I looking at? (I guess that's always the biggest concern).

Thanks,

Kevin

[Paul Young]

Re: '81 Vette: Car's too fast!!

I too purchased a 71 Corvette with too much cam. On top of that I had a pesky vacuum leak on the bottom of the intake from what I assumed was a head shave. I installed Rhodes lifters which tamed the cam down considerably at idle and still created more vacuum,power, and gas mileage. I have been pleased with the lifters which are supposed to bleed down at low RPM and pump up at higher RPM. They have done everything that they claimed they would do and only retail for about $80. You might consider that if economics is a factor.

[Paul Young]

Re: '81 Vette: Car's too fast!!

I too purchased a 71 Corvette with too much cam. On top of that I had a pesky vacuum leak on the bottom of the intake from what I assumed was a head shave. I installed Rhodes lifters which tamed the cam down considerably at idle and still created more vacuum,power, and gas mileage. I have been pleased with the lifters which are supposed to bleed down at low RPM and pump up at higher RPM. They have done everything that they claimed they would do and only retail for about $80. You might consider that if economics is a factor.

[John]

Re: '81 Vette: Car's too fast!!

I have a 75 that as you say is hot rodded. I have done the work myself and can safely say that you won't like the performance of the stock engine. You can trick out the carb and set the idle between 800-900 RPM and the engine should settle out enough to be tolerable unless there is a monster cam in there. The stock Q-jet properly blueprinted will work more than adequate. I am producing roughly 330 HP without headers and the car idles good @ 800RPM..Make sure the carb isn't leaking internally. I have also trued the heads (S/R Torquers) .025 without any problems. Good Luck!

[John]

Re: '81 Vette: Car's too fast!!

I have a 75 that as you say is hot rodded. I have done the work myself and can safely say that you won't like the performance of the stock engine. You can trick out the carb and set the idle between 800-900 RPM and the engine should settle out enough to be tolerable unless there is a monster cam in there. The stock Q-jet properly blueprinted will work more than adequate. I am producing roughly 330 HP without headers and the car idles good @ 800RPM..Make sure the carb isn't leaking internally. I have also trued the heads (S/R Torquers) .025 without any problems. Good Luck!