Used LT1 350 Camshaft Swap Into Truck Block w/Vortec Heads?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Majoraslayer

I'm Awesome
Joined
Nov 30, 2023
Messages
110
Reaction score
99
Location
USA
Most of you have probably already seen me post about this in other threads, but I'm going to start a new thread specific to this part of my project.

I have a TBI block with roller cam provisions that I'm swapping Vortec heads onto, and will be retaining TBI with it. I've read some posts on Camaro forums mentioning that it's apparently a somewhat common swap to put a factory LT1 camshaft into a TBI/TPI 350 engine, and they're mild enough to play fairly nicely with them for just a little more grunt. I'll have to actually get hands on with it to understand this better, but there's supposedly just a dowel pin of some sort you can drive in on the LT1 camshaft to make it fit into other 350 blocks.

I also have a 1993 Camaro LT1 block just sitting around with no plans for using it, so I'd like to pull the used cam out of that block and reuse it in my truck's block (granted it's in good shape). The plan is to take the retainer hardware, rocker arms, lifter rods and lifters out of the LT1 along with the camshaft itself and reinstall them in my truck engine in the same locations.

The first question I've run into (and there will probably be more): do I need to run the LT1 valve springs with the camshaft, or will the Vortec OEM springs work? I noticed that the part numbers for the springs are different between Vortec and LT1 engines, and I think the springs for the LT1 heads are taller. One of the videos I've watched to learn more about working with Vortec heads mentioned that the guide bosses in the Vortec heads typically need to be modified at a machine shop if larger springs are needed. Will Vortec springs be able to work well with the LT1 cam, or will I have to get this modification to transfer the springs from the LT1 heads to the Vortecs?
 

Supercharged111

Truly Awesome
Joined
Aug 20, 2015
Messages
12,771
Reaction score
15,615
You're going to want to just get different springs period. Vortec springs go in at like 1.72". You can use LS6 springs and offset locks.

Early LT1 cam won't have that extended pin to knock in, they spun the opti with a splined shaft that slides into the cam so easy peasy for you. You can also use the roller lifters, spider, etc from the LT1.

You're going to want to shift it at least at 5500 RPM, so keep that in mind. You might advance the cam for more torque and knock a little off the WOT shift point.
 

Majoraslayer

I'm Awesome
Joined
Nov 30, 2023
Messages
110
Reaction score
99
Location
USA
You're going to want to just get different springs period. Vortec springs go in at like 1.72". You can use LS6 springs and offset locks.

Early LT1 cam won't have that extended pin to knock in, they spun the opti with a splined shaft that slides into the cam so easy peasy for you. You can also use the roller lifters, spider, etc from the LT1.

You're going to want to shift it at least at 5500 RPM, so keep that in mind. You might advance the cam for more torque and knock a little off the WOT shift point.
It's a 700R4 in a 1988 truck, so no electronic shift control. How would you adjust for that, change to a different stall torque converter?
 

Supercharged111

Truly Awesome
Joined
Aug 20, 2015
Messages
12,771
Reaction score
15,615
It's a 700R4 in a 1988 truck, so no electronic shift control. How would you adjust for that, change to a different stall torque converter?

Nope, just buy a governor kit for it.


Without it you'll be shooting yourself in the foot as it'll upshift before peak hp with the lame L05 setup.
 

Majoraslayer

I'm Awesome
Joined
Nov 30, 2023
Messages
110
Reaction score
99
Location
USA
I'm still a little fuzzy on a lot of specs when it comes to camshafts and valve hardware. A quick search for LS6 springs landed me on a listing that states they're "PAC-1218 Drop-In Beehive Valve Springs, LS6 Compatible", and '600" Lift Rated'. Comp Cams lists an "Offset Dual Valve Spring Retainer" with 10° lock that adds an additional .100” installed height. Does that sound correct for what you're recommending? Would this still require machining on the guide bosses, or just install in the Vortec heads as they are?
 

Erik the Awful

Supporting Member
Supporting Member
Joined
Aug 9, 2019
Messages
7,873
Reaction score
16,230
Location
Choctaw, OK
I'm still a little fuzzy on a lot of specs when it comes to camshafts and valve hardware. A quick search for LS6 springs landed me on a listing that states they're "PAC-1218 Drop-In Beehive Valve Springs, LS6 Compatible", and '600" Lift Rated'. Comp Cams lists an "Offset Dual Valve Spring Retainer" with 10° lock that adds an additional .100” installed height. Does that sound correct for what you're recommending? Would this still require machining on the guide bosses, or just install in the Vortec heads as they are?
You'll want to do all the measuring and make sure the installed height is within spec. I don't know if the 787-16 retainers alter the installed height, but I know it was within spec. You'll also need to measure your valve seal to retainer clearance at full lift.

I did not have to do any machining on my guide bosses. My Vortec heads are untouched, although if they come back off they're getting a mild port job and I'm going to drill the coolant bypass.

Personally I would just bring the heads to your local machine shop and they should be able to easily check them out, do any work needed and fit them with the correct valve springs and seals for your combo.
Yeah, that's an option, but it's a lot cheaper to do it yourself. I don't have a whole lot of those wallet wrenches laying around.
 

Majoraslayer

I'm Awesome
Joined
Nov 30, 2023
Messages
110
Reaction score
99
Location
USA
Heads are at the machine shop now. I asked about the springs, and the machinist thinks the stock springs *should* be able to handle a stock 1993 LT1 F-body cam. A Google search led me to a post that indicates the max lift of that camshaft should be .480. I found another thread about the max lift stock Vortec heads can handle; a few people said that .480 is the absolute maximum, but "right around .470-.480 lift the bottom of the retainer starts to hit the top of the valve stem seal". Should I be worried? I'm up for second opinions; the machine shop surely knows what they're doing far better than I do, but he also seemed to be guessing off the top of his head without looking up anything about the specs I'm working with.
 
Last edited:
Top