LT1-LT4 Modifications 1993-97 Gen II Small Block V8

LT4 Hot Cam reground

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Old 11-28-2013, 10:34 PM
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Default LT4 Hot Cam reground

Hi Guys! Need some help with a cam that I bought! The cam has a stamp that reads GMPT BC-15-242. I believe that this is a z28 1995-96 cam. The cam was sent to Delta Camshaft and regrouped to 156 LT1 218-228 (-12)? Is this a LT4 Hot Cam with a fuel lobe or no fuel lobe? Thanks for your help! John.
Old 11-29-2013, 06:20 AM
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So you think you bought a stock LT1 cam that was reground to something near HOT cam specs and are asking if it has a fuel pump lobe? A fuel pump lobe looks a LOT different than a valve lift lobe, plus it would e a 17th lobe on the cam rather than the 16 needed for the 2 valves each per 8 cylinders.

Why don't you tell us what you are trying to accomplish.
Old 11-29-2013, 09:05 AM
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Default Cam help

O.k. I have a 1996 LT4 Corvette and wanted to upgrade to the lt4 hot cam! Had been looking for sum time before I found this one for sale. He said that this cam was a gm lt4 hot cam for $100.00. So I bought this cam and when I opened the box and looked at the cam I could see it was not a gm lt4 hot cam. Here are sum pics. Also came in box marked delta camshafts with numbers stated in earlier post as reground camshaft. Thanks John.
Attached Thumbnails LT4 Hot Cam reground-image.jpg  

Last edited by bornwild; 11-29-2013 at 09:18 AM. Reason: Add pics
Old 11-29-2013, 09:18 AM
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No pics. Any numbers on the cam itself? I'd get it checked out before installing it in any engine.
Old 11-29-2013, 09:23 AM
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Default Cam

Yes! On cam GMPT BC 15-242 at the end of cam 218-228-12? Pic.
Attached Thumbnails LT4 Hot Cam reground-image.jpg  
Old 11-29-2013, 09:26 AM
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Here is the last pic! Tried to post all three at one time but would not let me do so. Also checked the 17 th lobe and it looks like it has been ground down to almost nothing even all the way around.Thanks John
Attached Thumbnails LT4 Hot Cam reground-image.jpg  

Last edited by bornwild; 11-29-2013 at 09:40 AM. Reason: Spelling
Old 11-29-2013, 10:15 AM
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I'd take it to a machine shop to have it looked at before using it. The fuel lobe will not matter.
Old 11-29-2013, 10:20 AM
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Leave the car alone, let the dealer service it.
Old 11-29-2013, 10:23 AM
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Default Lt4 cam reground

O.k. I just know that the 17 the lobe is much smaller than the one on a true gm lt4 hot cam?
Old 11-29-2013, 10:27 AM
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Default Cam

Look I am going to have a pro do my engine. But with that said I am trying to get all the stuff together before the build. Just need some help with this cam. Thanks John.
Old 11-29-2013, 10:37 AM
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"professional" more often means "gets paid to do" rather than actually meaning anything about an individuals knowledge or skill level.
Old 11-29-2013, 11:04 AM
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Listen! If this is what you do for a living god bless you! I have my own exsperance in others areas! With that said if you can help me with this cam thank you and if you are not than please leave space for someone Elise to imput there info. Thanks John.
Old 11-29-2013, 12:11 PM
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Only things I can tell you is, you have EFI. The engine does not use a mechanical fuel pump therefore it does not matter about the fuel pump lobe. Have the cam checked to make sure it is what it is. Also check to make sure the snout does indeed accept a vented opti. Get references from whatever builder you are going to use. You want to do these things before anything is done to a new engine.
Old 11-29-2013, 02:45 PM
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OP

get a "Hot Cam" cam card and then have a machine shop measure your cam to see if it was ground to those specs.....pictures over the internet really won't tell me or anyone else exactly wtf that cam is.

confirm the nose does take a vented opti. confirn length of dowel pin is right.

I would think a used un-molested Hot Cam would be FS on the various F body forums or ebay . I know I have seen them advertised used for $100
Old 11-29-2013, 03:49 PM
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Even if the lift specs are the same it doesn't make it the same. Leave the regrinds to the Jasper rebuilds.
Old 11-29-2013, 04:53 PM
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yeah dwayne....I meant "all" measurements beyond just lift. IVO, IVC, EVO, EVC...assumeing the machine shop has the ability/knowledge to measure or determice them

with that said I would not run a regrind period. way to much work to to do a cam swap and put in a cam of suspect background as what it is or was
Old 11-29-2013, 05:31 PM
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Default Reground cam

O.K. Guys! Thank you so much for all the Information. I thought I was getting a G M hot cam but the guy sent me a reground one! So I will take the advice given me and get the real deal cam put this one back up for sale. Happy Holliday's to all.

Last edited by bornwild; 11-29-2013 at 05:33 PM. Reason: Spelling
Old 11-30-2013, 06:18 AM
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It would be easy for you to check the lobe lift on the cam with a set of calipers. Measure it at the peak, then measure it at the base and subtract. The lobe lift on a stock cam will be .298" intake and .306" exhaust. For a hotcam it's .328"/.328".
Old 11-30-2013, 08:22 AM
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Default Checking lobe lift

Thank you Sir! I will check this out! Happy Holliday's.
Old 11-30-2013, 08:37 AM
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Even if the specs seem the same grinding a cam on a smaller base circle makes it slightly harder to control so you could endup needing $150 valvespring setup instead of the $35 LT4 springs, if that is the case then a pushrod upgrade endsup being something more important to look at so even more money there.

The difference in controlling a given lift and duration when changing basecircle might be splitting hairs here but it is worth understanding that it is a factor.


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