[Jims56]

I have a stock L31 vortec 350, that has 2000 miles on it now. Was thinking of changing the camshaft out. I don't want to machine the heads. So would the RamJet 350 cam give me some noticeably difference? Worth the effort?
Thanks

 

[Jims56]

Well after I found the spec's on the Ramjet 350, I would say yes it would be an improvement and I should be able to just change the cam. Looking at the spec's on the ramjet I see the only difference between the two long blocks, is the cam and the 1.6 roller rockers, the ramjet has. So to get the full effect of the ramjet cam I would have to use the 1.6 rockers, correct. Question. One thing I haven't been able to find is. Are the push rods the same length between the two engines? Since they both use the same vortec head, I would think the slot in the head for the push rod would not need to be enlarged. Anyone done this change?

 

[Typhoontx]

there is a parts listing for a 350 ramjet on the internet , find the push rod p/n there then look up a L-31 vortec part listing and see if they are the same. I would think they would be the same but that's one way to confirm for sure.
That cam is going to pick up about 40 hp over a the stock L-31 cam. I would also replace the stock L-31 valve springs with something better as well

on an engine dyno a stock l31 with a airgap dualplane produces about 310hp

you can put a lt4 hotcam in a L-31 without machining the heads, it takes specific springs, seals and retainers , that cam would put you in the 380hp range and if you stay with 1.5 rockers you shouldn't have to enlarge the pushrod holes.

Here is a link showing some good pictures of measurements of the seal to retainer clearances
http://www.pacificp.com/forum/viewt...p?t=8710&postdays=0&postorder=asc&start=20&sid=2714d59cad5fe338a921af17e3eac8ef

Regards, Robert

 

[Jims56]

there is a parts listing for a 350 ramjet on the internet , find the push rod p/n there then look up a L-31 vortec part listing and see if they are the same. I would think they would be the same but that's one way to confirm for sure.
That cam is going to pick up about 40 hp over a the stock L-31 cam. I would also replace the stock L-31 valve springs with something better as well

on an engine dyno a stock l31 with a airgap dualplane produces about 310hp

you can put a lt4 hotcam in a L-31 without machining the heads, it takes specific springs, seals and retainers , that cam would put you in the 380hp range and if you stay with 1.5 rockers you shouldn't have to enlarge the pushrod holes.

Here is a link showing some good pictures of measurements of the seal to retainer clearances
http://www.pacificp.com/forum/viewt...p?t=8710&postdays=0&postorder=asc&start=20&sid=2714d59cad5fe338a921af17e3eac8ef

Regards, Robert

Thanks for that info Robert, great stuff.

 

[REBEL57]

Still love this 56 it's just right.

 

[gogburn]

There is an excellent discussion of the L-31 and it's upgrades posted by member Hog in this thread, post #4. It addresses some of your questions.

http://www.trifive.com/forums/showthread.php?t=107242

 

[Jims56]

There is an excellent discussion of the L-31 and it's upgrades posted by member Hog in this thread, post #4. It addresses some of your questions.

http://www.trifive.com/forums/showthread.php?t=107242

Thanks guys.

 

[hotrodg726]

I have a good used ramjet 350 camshaft available for a reasonable cost.

 

[rogueant]

hey jim

check out the lt1/lt4 hot cam, while i was looking into cams this one was recommended by a few guys as perfect for a vortec motor. lift is too high with 1.6 rockers used on the lt1 but should be fine with the vortec 1.5 rockers.
valve springs on stock vortec heads are not real good from what i've read, that's why i got the comp cams beehive springs