Were small-cap HEI distributors used only on roller engines?
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From: Cleveland, OH
Car: '87 Camaro LT
Engine: 355 L98
Transmission: T56
Were small-cap HEI distributors used only on roller engines?
I have an LT4 hot cam with a carb and large cap HEI distributor. I need to replace the distributor gear with a melonized one. I have a spare small-cap HEI but I don't know what it came out of. Is it safe to assume it came out of a roller cam engine and I can rob the distributor gear out of it for my large cap distributor? I have to measure the shaft diameters yet but from what I've read I think I'll need to bore the gear up to .491" from .428".
Last edited by Ukraine Train; Nov 28, 2012 at 12:03 PM.
Re: Were small-cap HEI distributors used only on roller engines?
I have an LT4 hot cam with a carb and large cap HEI distributor. I need to replace the distributor gear with a melonized one. I have a spare small-cap HEI but I don't know what it came out of. Is it safe to assume it came out of a roller cam engine and I can rob the distributor gear out of it for my large cap distributor? I have to measure the shaft diameters yet but from what I've read I think I'll need to bore the gear up to .491" from .420" or so.
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From: Philly, PA
Re: Were small-cap HEI distributors used only on roller engines?
Or you could just leave the stock flat tappet cam gear on your existing HEI and just stab that puppy in. They work just fine on factory roller cams. Done it too many times to remember them all.
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From: Cleveland, OH
Car: '87 Camaro LT
Engine: 355 L98
Transmission: T56
Re: Were small-cap HEI distributors used only on roller engines?
I ran the stock gear for a while before I learned that you're supposed to match it to the cam material and I can see excessive wear on it. I'd rather do it right, especially since I already have a gear to use. There's a machine shop at work that will bore it for me.
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: Were small-cap HEI distributors used only on roller engines?
LT4 hotcam does not require a special distributor gear. Like previously said, the factory roller cams come with a melonized distributor gear on the cam.
Aftermarket billet cams require a different gear.
Aftermarket billet cams require a different gear.
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Car: 85 Trans Am
Engine: 98 Vortec 350 LT1 Cam w/ TPI
Transmission: T56
Axle/Gears: 9 bolt 3:27
Re: Were small-cap HEI distributors used only on roller engines?
.491 gear
http://www.summitracing.com/parts/ac...6413/overview/
.428 gear
http://www.summitracing.com/parts/nal-19052845
Both melonized
http://www.summitracing.com/parts/ac...6413/overview/
.428 gear
http://www.summitracing.com/parts/nal-19052845
Both melonized
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From: Cleveland, OH
Car: '87 Camaro LT
Engine: 355 L98
Transmission: T56
Re: Were small-cap HEI distributors used only on roller engines?
But this cam was originally designed for factory roller engines that already had a melonized distributor/oil pump drive gear, right? So if I have a cast iron gear on my old big cap HEI distributor, why wouldn't I need to change it to a melonized gear?
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Joined: Dec 2004
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: Were small-cap HEI distributors used only on roller engines?
I read your previous posts alittle too quick.
I do not know about the cast gears.
So when are you getting it bored? Hope it all works out for you.
I do not know about the cast gears.
So when are you getting it bored? Hope it all works out for you.
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From: Chasing Electrons
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Engine: check
Transmission: check
Re: Were small-cap HEI distributors used only on roller engines?
Many trucks used the small cap HEI/CC distributors and still had a flat tappet cam. If the distributor is from a f-body, then it is a roller cam distributor. IIRC, the small cap distributors started in '88 in f-body's with the TBI engines.
RBob.
RBob.
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From: Cleveland, OH
Car: '87 Camaro LT
Engine: 355 L98
Transmission: T56
Re: Were small-cap HEI distributors used only on roller engines?
That's good to know about truck engines. I suppose I can take the easy way out and just buy a new gear. Or maybe I can get the QC lab at work to check the hardness and compare it to cast iron. There should be an obvious difference.
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From: Howard Lake, MN
Car: 86 Camaro
Engine: 355- hopefully a 5.3 this summer
Transmission: 700r4
Axle/Gears: 3.42
Re: Were small-cap HEI distributors used only on roller engines?
i put about 20,000 miles over a period of 4 years on the 355 that was in my 71 Nova with the HOT cam and whatever random mid 70's HEI distributor i had laying around when i put it together, and i never saw any evidence of any sort of wear on the gears or felt any play in the dozens of times i had the distributor out for various reasons.
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