Buying my first (and long-dreamed-of) Vette and would appreciate any help on engine question ... What's the significance of the original solid lifter camshaft in 350/370 LT1 having been replaced with a hydraulic lifter camshaft? Thanks for response. - Chris
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Re: 1970 LT1 Solid Lifter Cam Replaced w/ Hydrauli
I guess it means someone replaced the best street SB cam ever made with God knows what?
You can still buy them, so the damage can be undone, but what else has been messed with?
Duke -
Re: 1970 LT1 Solid Lifter Cam Replaced w/ Hydrauli
The question you should be asking is "replaced it with what???". LT1 is a great cam (I use it) but just because the owner replaced it doesn't mean that the car is shady or the owner was a bubba. Maybe he wasn't interested in setting the lash, maybe he wanted different torque charastertistics, maybe he didn't like the sound of the exhaust or the lifters.... could be lots of reasons to choose a hydraulic cam over the LT1.Comment
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Re: 1970 LT1 Solid Lifter Cam Replaced w/ Hydrauli
I suspect you're right about the owner's motivations ... the car has been well cared for and mechnically most everything appears to be correct. More generally, can you help me understand better "what makes an LT1 an LT1?" This car appears to have its original engine with the LT1 heads and Holley four-barrel carb. But without the solid lifter cam -- typically the first component mentioned in the literature about the LT1 option new to 1970 -- is this car more LT1 or more standard small block?
How do you think the cam change would affect performance or hp? Would you restore it to orginal specs? What would it take?
Thanks again for helping this newbie.
ChrisComment
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Re: 1970 LT1 Solid Lifter Cam Replaced w/ Hydrauli
Chris-----
It's very hard to say "what one would call the engine now" not knowing what sort of cam it has in it. However, understand that a 1970 LT-1 and L-46 are roughly equivalent engines except for the camshaft---the LT-1 has a particular mechanical lifter grind and the L-46 has a high performance solid lifter grind. The exact same thing could be said of 1971-72 LT-1 versus 1973+ L-82---they are roughly equivalent engines except for camshafts.
Others might be quick to say that the intake manifolds and carburetors are also different between LT-1 and L-46/L-82. That's true, but there's really not a lot of performance difference generated by these components. The LT-1's Holley and the L-46/L-82 Q-Jet are roughly the same in terms of CFM.
So, in general and as a ROUGH comparison, I would say that what one has if one replaces the mechanical lifter cam in a 1970 LT-1 with an hydraulic lifter grind is an L-46. Of course, depending on what hydraulic lifter cam is installed, it's VERY possible to have an engine with a power output GREATER than that produced by the original LT-1 mechanical lifter cam. I don't know what one would call such an engine. It would have no "kinship" with any GM RPO engine.In Appreciation of John HinckleyComment
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Correction
The 3rd line of the first paragraph in my above response should say that the "...L-46 has a high performance HYDRAULIC LIFTER grind" and NOT a "solid lifter grind".In Appreciation of John HinckleyComment
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Re: 1970 LT1 Solid Lifter Cam Replaced w/ Hydrauli
A small response to this one...Basically a LT1 cam was made to work with a certain engine combo and specifically the compression ratio. So if they changed the cam, chances are they changed a lott more, because it a lott of hasle to do with the engine in the car.
YvesComment
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