GMJim

I bought a 68 SWB Chevy fleetside pickup with a 4.8 LS and it has a Comp cams 54-456-11 installed by the previous owner in it. Basically all stock except for valve springs and long tube headers. It runs like crap and I can't get it to idle low enough for the stock converter and keeps throwing MAP codes. I was planning on putting the stock cam back in it and a stock tune and be done with it. I've been a mechanic for 36 years but I don't have tuning skills and am relying on a friend who has HP tuners but he doesn't have that much experience either. I called comp cams for advice and they told me I would need a stall converter for this cam and suggested I put in a 54-408-11 instead. I'm very apprehensive to do this because I'm afraid tuning it would be too difficult for me. How much tuning beyond the stock settings would be required for this cam or is there a better way for me to go?

I've done several searches and a lot of reading on this and other forums but I'm still uncertain what to do. Any advice would be greatly appreciated.
Thanks

gamble686

iTrader: (3)

You can get a mail order tune with that very easily. Where do you live? Would be much cheaper to just get a proper tune done. A lot more fun too.

GMJim

A friend of mine has HP Tuners. All I need to know is how far off the stock tune do I go and where?
Thanks

superspirit

You have to start with data logging, to find out whats going on and when it's going on, then you would adjust your timing and fuel curves as necessary, there is no easy way to do custom tuning, you need a wideband 02 also. good luck.

gamble686

iTrader: (3)

HPTuners TUNING GUIDE
That's a good place to start.

GMJim

Thanks everyone. I have an LM1 wideband A/F meter that I've used for years tuning carburetors. I don't have HP tuners of my own and don't think I want to spend $499.00 for it. I really don't have the patience to go through all the trial and error and the steep learning curve of tuning my 4.8. I'll just put a stock cam in it and flash the stock tune back in it.

Thanks for all the help and advice.