Stock 305 cam.

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Mjferreira

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Hi all,

I was doing some research on the stock engine in my truck and read on Wikipedia the 305 TBI (L03) has a hydraulic roller cam. Does anyone know of this is true?
 

PlayingWithTBI

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I was doing some research on the stock engine in my truck and read on Wikipedia the 305 TBI (L03) has a hydraulic roller cam.
It's possible. What year, what vehicle? Don't believe everything you read in Wikipedia.
 

BOOT

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Yah don't think until vortecs in 96 that all had roller cams. But I've read some(few) random TBI engines had roller cams, some were machined for them but didn't have one and some blocks had the right bosses but no machining.
 

PlayingWithTBI

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But I've read some(few) random TBI engines had roller cams
Yeah, FWIU most cars had rollers, an occasional truck did too but, I think they got them because the factory ran out of flat tappets and had to fill the order, ha ha. My Mr Goodwrench flat tappet block has the bosses for a roller and I'm just finishing up replacing my wiped out flat tappet now.

This would apply to converting a 305 too...
www.gmt400.com/threads/my-flat-tappet-cam-wiped-out-so-i-decided-to-go-roller.60167/
 

PWC Repair

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The roller cam started in the cars in '87.......some late build '86 got them too. We're talking Corvette, Camaro, Firebird. In the trucks it wasn't available until '96 I believe.
 

L31MaxExpress

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The roller cam started in the cars in '87.......some late build '86 got them too. We're talking Corvette, Camaro, Firebird. In the trucks it wasn't available until '96 I believe.
My uncles 94 350 had a factory roller. It was the OEM engine that had never been apart.

I also pulled several factory TBI 305/350 roller engines from trucks and vans that had the partial vin stamp on the block matching the wrecked vehicle they were in. No reason to believe at that point in the early 2000s that the engine had ever been removed or altered from the way it was delivered. In some of the 92-94 trucks I have seen 083/217 TPI style non-swirl heads as well with date codes that closely match the blocks they were on. GM is well known to play with engine setups in certain applications to test ideas for a wider range of production. Aluminum block 5.3L with 799/243 heads and flat top pistons on the L33 5.3L that only came in Extended Cab 4x4 GMT800s for example. That was GMs real world test setup for the GenIV setup.

GM first tested analog port fuel injection in the 70s, TBI on a couple of early 80s models before it spread across the board. Same with SFI and DIS systems.
 
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PWC Repair

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I've heard of these sparsely scattered roller cam engines but maybe just test mules as you stated. All the blocks on the TBI engines are 'ready' for a roller cam setup. I guess people could have also swapped the stuff in. Either way, they really only came 'standard' in the TPI setups, then 'Vortec' in '96.
 
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