Need help with Cam choice
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Pro
Joined: Nov 2004
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From: Frisco TX
Need help with Cam choice
OK, so I have an 89 and have had it for about 12 years. It's been a great car but it's time for a change.
So I am pulling the motor and trans (700r4) and dropping them into a 1933 Ford Roadster (a factory five kit). I'll go through the motor before I put it in the new car and as it will be apart I figured I might as well upgrade a couple items :-) . First, I am removing the TPI and for now will be going with a carburetor. This should remove the breathing issue of the system keeping the RPMs below 5500.
Any how, next I want to replace the cam. I know that plenty of guys on here have replaced the cam with the ZZ4 cam and have given it great reviews. I know it performs better but what is the idle like with the cam? I know most of the time they advertise a good smooth idle but I don't want a good smooth idle. What I would really like is a nasty idle with a rumble sitting at the light. BUT SWMBO has to be pleased with riding in the car as well so I will just have to go with a slightly dirty idle. Any one have a good suggestion of a cam that will match the motor?
Tim
So I am pulling the motor and trans (700r4) and dropping them into a 1933 Ford Roadster (a factory five kit). I'll go through the motor before I put it in the new car and as it will be apart I figured I might as well upgrade a couple items :-) . First, I am removing the TPI and for now will be going with a carburetor. This should remove the breathing issue of the system keeping the RPMs below 5500.
Any how, next I want to replace the cam. I know that plenty of guys on here have replaced the cam with the ZZ4 cam and have given it great reviews. I know it performs better but what is the idle like with the cam? I know most of the time they advertise a good smooth idle but I don't want a good smooth idle. What I would really like is a nasty idle with a rumble sitting at the light. BUT SWMBO has to be pleased with riding in the car as well so I will just have to go with a slightly dirty idle. Any one have a good suggestion of a cam that will match the motor?
Tim
Le Mans Master
Joined: Feb 2005
Posts: 6,479
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From: Clearwater Florida
..... Give Comp Cams a call ... sounds like you're looking for a "thumper" cam ... the ZZ4 is a great choice for a TPI motor , but since you're changing over to a carburetor a different door has been opened in the cam selection room .....
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Joined: Sep 2001
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From: Glenbeulah Wi
OK, so I have an 89 and have had it for about 12 years. It's been a great car but it's time for a change.
So I am pulling the motor and trans (700r4) and dropping them into a 1933 Ford Roadster (a factory five kit). I'll go through the motor before I put it in the new car and as it will be apart I figured I might as well upgrade a couple items :-) . First, I am removing the TPI and for now will be going with a carburetor. This should remove the breathing issue of the system keeping the RPMs below 5500.
Any how, next I want to replace the cam. I know that plenty of guys on here have replaced the cam with the ZZ4 cam and have given it great reviews. I know it performs better but what is the idle like with the cam? I know most of the time they advertise a good smooth idle but I don't want a good smooth idle. What I would really like is a nasty idle with a rumble sitting at the light. BUT SWMBO has to be pleased with riding in the car as well so I will just have to go with a slightly dirty idle. Any one have a good suggestion of a cam that will match the motor?
Tim
So I am pulling the motor and trans (700r4) and dropping them into a 1933 Ford Roadster (a factory five kit). I'll go through the motor before I put it in the new car and as it will be apart I figured I might as well upgrade a couple items :-) . First, I am removing the TPI and for now will be going with a carburetor. This should remove the breathing issue of the system keeping the RPMs below 5500.
Any how, next I want to replace the cam. I know that plenty of guys on here have replaced the cam with the ZZ4 cam and have given it great reviews. I know it performs better but what is the idle like with the cam? I know most of the time they advertise a good smooth idle but I don't want a good smooth idle. What I would really like is a nasty idle with a rumble sitting at the light. BUT SWMBO has to be pleased with riding in the car as well so I will just have to go with a slightly dirty idle. Any one have a good suggestion of a cam that will match the motor?
Tim
I agree with calling comp cams but in my opinion if you keep a stock TPI engine and just replace the injection with a carb the LT1 Hotcam is a good choice. It will work well with the mechanical limitations of the engine and have a more aggressive idle then what you have now.
Thread Starter
Pro
Joined: Nov 2004
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From: Frisco TX
Thanks for the input guys... It looks like Comp Cams will be getting a call just to cover everything.
I went to the Summit site and looked at the LT1 Hot Cam. Says that it was designed to use a 1.81 rocker. Any one know what comes in the stock L98?
Tim
I went to the Summit site and looked at the LT1 Hot Cam. Says that it was designed to use a 1.81 rocker. Any one know what comes in the stock L98?
Tim
Safety Car
Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
Something is wrong with the description, is is designed to be used with 1.6 rockers, but will work fine with 1.5 rockers. The stock rocker is 1.5
2nd Gear
Joined: May 2017
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hot cam is a bad idea
OK I have that motor in my 87, its a great street motor, it is designed to produce all its power and torque at lower RPM and that's where you want it on the street.
That being said, glad to here you chucked the TPI, the heads are 170cc intake runners and don't breath above 4300 RPM very good, also they are bad about burning through to the water jacket at the lower side, by the spark plug.
Now as far as the cam, if you go for wild duration it will be a pig, with the breathing problem and low compression.
What you want to do is spice up the lift and duration just a pinch, but what you really want to do is get a cam with a lower LSA, that will throw the power and tongue lower in the RPM range to go with those heads, also if you want the nasty cam sound that will do it while increasing the performance for street use. now you might have vacuum problems with the lower LSA but you can use a vacuum can or aux pump to cure that.
Also I would deck the block and get rid of the quench area between the head and piston, then use a head gasket with .040 compressed thickness. This will do good at lowering the tendency for per-ignition.
Just watch your compression ration don't go to high.
That being said, glad to here you chucked the TPI, the heads are 170cc intake runners and don't breath above 4300 RPM very good, also they are bad about burning through to the water jacket at the lower side, by the spark plug.
Now as far as the cam, if you go for wild duration it will be a pig, with the breathing problem and low compression.
What you want to do is spice up the lift and duration just a pinch, but what you really want to do is get a cam with a lower LSA, that will throw the power and tongue lower in the RPM range to go with those heads, also if you want the nasty cam sound that will do it while increasing the performance for street use. now you might have vacuum problems with the lower LSA but you can use a vacuum can or aux pump to cure that.
Also I would deck the block and get rid of the quench area between the head and piston, then use a head gasket with .040 compressed thickness. This will do good at lowering the tendency for per-ignition.
Just watch your compression ration don't go to high.
Safety Car
Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
This post in the for sales section may interest you? Rockers and springs for the hotcam.
http://www.corvetteforum.com/forums/...s-springs.html
http://www.corvetteforum.com/forums/...s-springs.html
