Custom Grind Cam Specs?

[Jon7I2]

Alright, I’ve decided to jump into the heads and cam game, and I have a few questions. I have a 99 M6 Formula w/ dynatech supermaxx LT header system, cutout, lid and bellows, ported throttle body/ bypass, March underdrive pulley, chromemoly pushrods, and a few suspension things. I am pretty set on CNC LS6 ported heads from texas-speed, but I am not 100% sure on a matching cam. I am sure that I want to go with a custom grind though, and I had a guy spec me a couple different custom crane cams — 228/232 .600/.600 112+4, and 232/236 .624/.624 112+4. What does the + 4 mean after the LSA? I’m assuming that just means that you could get it in 112,113,114,115, or 116, Is that correct? I am pretty sure I want to go with the first spec, because I understand it has a very street useful torque curve, and that’s what I mainly want, to be fast on the street. I have called a number of different vendors and every time I ask them about the specs of the first cam, in regards to where my powerband would be w/ what as my peak, I get relatively vague answers. I just want to know if the 228/232 .600/.600 112+4 would be the ideal street cam for my setup, and if it would properly match the heads. The valves of those LS6 heads are 2.00 1.55, and the flow intake bench numbers are:
ValveLift Intake
.100" 72
.200" 149
.300" 205
.400" 255
.500" 287
.600" 307
.625" 310

Also would a cam of this size need bigger pound fuel injectors? I have a 99 so I got stuck with the 26 pound injectors. Does anyone else have a similar cam or the exact same specs with some power numbers or perhaps a dyno sheet? Thanks a lot, and I really look forward to what everyone has to say.

[mrr23]

the +4 means the cam is ground 4* advanced from straight up. this is mainly done to counter timing chain stretch. also, by advancing/retarding the cam, you move the power band down/up.

[secondgearscratch]

the +4 means the cam is ground 4* advanced from straight up. this is mainly done to counter timing chain stretch. also, by advancing/retarding the cam, you move the power band down/up.

THANK YOU!!

i was trying to find out what that number signified and explain it to myself but i couldnt get an accurate description. how does that affect the lobes?

[Jon7I2]

the +4 means the cam is ground 4* advanced from straight up. this is mainly done to counter timing chain stretch. also, by advancing/retarding the cam, you move the power band down/up.

So, it's like the higher the LSA the more of a "flat" torque curve you will have right? So then what is the difference between a 112 + 4 and a straight up 116?

[mrr23]

THANK YOU!!

i was trying to find out what that number signified and explain it to myself but i couldnt get an accurate description. how does that affect the lobes?

it doesn't affect the lobes directly. it affects the opening/closing events. for instance, let's say the intake valve opens at 45* ATDC. by advancing it 4*, it now opens up at 41* ATDC.

[mrr23]

So, it's like the higher the LSA the more of a "flat" torque curve you will have right? So then what is the difference between a 112 + 4 and a straight up 116?

they don't add together. the +4 changes when the valves open up.
http://vincihighperformance.com/LS1%...SA%20EXPLAINED