Are mild cam swaps worth the effort?

[Frankenchevy]

I have an L31r vortec 350, roughly 4000 miles on engine. Basic mods to date: long tube headers to 2-1/2” duals with H pipe, sniper efi, weiand street warrior dual plane intake, ecu controlled ignition, msd 6efi CDI box. Mods probably haven’t added much HP, just drivability mods.

I’m changing efi systems to the eddy pro flo 4 which will come with a new intake manifold—so that’ll already be off.

Question is:

is it really worth the effort of swapping a mild cam in? Am I only gaining 10 hp? Here’s the cam I had in mind, although come forth with ye recommendations if thou hath.

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[shiftpro]

Best to try find your current cam specs... compare the two together.
Until you know exactly what you have try not to make any choices.

I take it your current engine is a roller? So, you will be using the stock roller lifters? Just asking because new roller lifters would cost more than the cam.

 

[Rusty Nail]

It is a lot of work AND thars a lot of money! I thought you had to get a 215-222 to make it worthwhile re: power per dollar cuz that is mild AF. What do they got at a half inch of lift? LoL that's where id start lookin lmao. Im not the best guy to axe prolly.

Thats a lot of effing work.

 

[75gmck25]

Stock cam is probably about 192/195, so you should easily feel the difference with a 206/212. Power increase will be at a low/medium RPM, so very useful for a work truck, but it won’t be a major change.

You have good flowing cylinder heads that are much better flow than reworked stock heads, so a cam change is an excellent idea. Make sure you try moving base timing up to about 16 BTDC, and richen the idle and cruise circuits on the EFI to take advantage of the additional flow. One reason you might not feel that cam as much is that you are moving more air without adding fuel to match. However, your headers and intake should work well with it, so adjusting the EFI should get you a lot better performance.

Many guys read cam swap articles about lightweight cars with low gear ratio rear ends, and then can’t figure out why that new 230/230 cam doesn’t work well with their 3.08 gears and 33” tires in a 5000 lb truck. Your cam swap is a good match for a stock ratio auto trans truck with Vortec heads, but you could do more if you look at the entire package (trans/torque converter/ rear end ratio/ tire size/ headers).

Do you still have stock CUCV trans and gears? Pickups had a TH400 and about 4.56 gears, IIRC. You could handle more cam duration with your setup if you don’t have oversized tires, but may want to look at using a different torque converter.

Bruce

 

[legopnuematic]

Also calculate what your static and dynamic compression ratios are, thats another thing that people goof up on with cam swaps is they want that chop and lope and put way too much cam in a 7.2:1 small block and it can't get out of its way.

That cam you have listed might be pushing it for LSA, with EFI, IIRC most EFI's prefer around 112lsa.

My 76 I put a Howards cam in it based on what they had recommended for me with my heads, compression, intake and intended usage, they did a good job as my truck has great drivability and does certainly perform better than before (with headers, heads and intake with the cam). Right now its got too much tire and not enough gear (3.08 with 31's), but it still pulls pretty good for a heavy truck, with compressor in bed and all.

 

[Frankenchevy]

Best to try find your current cam specs... compare the two together.

Stock cam that Chevy ships in a new vortec block. I bought it as a long block from them a couple year ago. Yeah, the L31 is a factory roller.

It is a lot of work AND thars a lot of money! I thought you had to get a 215-222 to make it worthwhile re: power per dollar cuz that is mild AF. What do they got at a half inch of lift? LoL thars where id start lookin lmao. Im not the best guy to axe prolly.

Thats a lot of effing work.

This cam is pretty close to the max lift a vortec head can clear without swapping ls6 springs or machining.

Do you still have stock CUCV trans and gears? Pickups had a TH400 and about 4.56 gears, IIRC. You could handle more cam duration with your setup if you don’t have oversized tires, but may want to look at using a different torque converter.

I have 3.73s now and I’m swapping in an nv4500. With the EFI, I just set what AFR I want at a certain rpm/vacuum setting and it adds or pulls fuel to hit that target. It’s pretty dummy proof there.

As far as timing, I’ll have to look at my timing table, but I think the lowest command value is at least 16 now, but that’s factoring base+vac adv.

Do any of those factors alter your opinion of the chosen cam?

Also calculate what your static and dynamic compression ratios are, thats another thing that people goof up on with cam swaps is they want that chop and lope and put way too much cam in a 7.2:1 small block and it can't get out of its way.

That cam you have listed might be pushing it for LSA, with EFI, IIRC most EFI's prefer around 112lsa.

I think the vortec stock is around 9.5:1. I’ll ask comp about the lsa.

Thanks Guys!

 

[Bextreme04]

I would recommend you call Delta Camshaft in Tacoma, WA and talk to someone up there. I had my factory 454 roller cam reground and it was $144 shipped. They can regrind to whatever spec you want and can recommend a good grind for your specific application. Just tell them exactly what you want and what you currently have.

The aftermarket intake, exhaust, and adjustable EFI means you should pick up WAY more than 10hp from a cam change.

 

[Raider L]

Franenchevy,

I had a Comp Cams 280/480, .225 @ .050" when I first built my 350. It had huge mid range when it would start coming in at about 2200-2300 rpm. It had an initial timing at 12 degrees and a total of 34 degrees. It was fun for about a year but I decided to get something better on gas. That cam got about 5-6 mpg on the street and about 9 on the super slab. So I changed it to a Lunati "duel pattern" that's about, I think without looking at my cam card maybe 220/430...I think? And .205 @ .050. My gas milage doubled to 12 in town and depending on how fast on the slab 15 to 18 on the hyw. Now initial is 8 but I have it set at 10 degrees and all in at 30 degrees.

Bextreme04, is correct. There are alot of good cam regrinders who'll save you alot of money. And you can save youself a ton on headwork to. Those vortec heads can take alot of opening up to great advantage for electronic fuel injection . Even gasket matching can do some good. There are a ton of tricks and all kinds of stuff to do. Since you have your intake off, and I don't know about roller lifters, Bextreme04, can he put a lifter valley cover on those engines to keep the hot oil off the underside of the intake? Do the lifters get in the way or do they make one for rollers? I have one on mine and it's great. You can see the difference in miles per gal. due to cold gas!

 

[Frankenchevy]

Franenchevy,

I had a Comp Cams 280/480, .225 @ .050" when I first built my 350. It had huge mid range when it would start coming in at about 2200-2300 rpm. It had an initial timing at 12 degrees and a total of 34 degrees. It was fun for about a year but I decided to get something better on gas. That cam got about 5-6 mpg on the street and about 9 on the super slab. So I changed it to a Lunati "duel pattern" that's about, I think without looking at my cam card maybe 220/430...I think? And .205 @ .050. My gas milage doubled to 12 in town and depending on how fast on the slab 15 to 18 on the hyw. Now initial is 8 but I have it set at 10 degrees and all in at 30 degrees.

Bextreme04, is correct. There are alot of good cam regrinders who'll save you alot of money. And you can save youself a ton on headwork to. Those vortec heads can take alot of opening up to great advantage for electronic fuel injection . Even gasket matching can do some good. There are a ton of tricks and all kinds of stuff to do. Since you have your intake off, and I don't know about roller lifters, Bextreme04, can he put a lifter valley cover on those engines to keep the hot oil off the underside of the intake? Do the lifters get in the way or do they make one for rollers? I have one on mine and it's great. You can see the difference in miles per gal. due to cold gas!

The manifold doesn’t flow fuel on the new setup, only air. However, it is an air gap type manifold, which will keep the air charge a bit cooler.