EKCtransport Posted September 10, 2021 Share Posted September 10, 2021 Hi guys I have 1994 Mack 688s with a 350 that has never been modified and not really happy with the power I’m getting. What do you recommend to increase my power without getting too out of hand and causing issues? Thank you Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/ Share on other sites More sharing options...
0 alex g Posted September 10, 2021 Share Posted September 10, 2021 Do you have a boost gauge? You should be running 25 lbs at least. Alot of power issues derive from this. Just a idea before you start modifying Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479692 Share on other sites More sharing options...
0 EKCtransport Posted September 10, 2021 Author Share Posted September 10, 2021 Ya I’m getting just over 25lbs now put all new boots and clamps on tested the charge air cooler all is good. Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479702 Share on other sites More sharing options...
0 Glensts Posted September 11, 2021 Share Posted September 11, 2021 26 was all we got for boost with ours. Best money spent was rebuild pump and injectors, seemed to smarten ours up. Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479712 Share on other sites More sharing options...
0 Joey Mack Posted September 11, 2021 Share Posted September 11, 2021 just curious.... what tranny and rears and tire size do you have? The E-7 can pull really good.... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479713 Share on other sites More sharing options...
0 EKCtransport Posted September 12, 2021 Author Share Posted September 12, 2021 I have a 8ll 24.5s and 4 17 gears. Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479814 Share on other sites More sharing options...
0 Joey Mack Posted September 12, 2021 Share Posted September 12, 2021 I'm no Gearing Guru..... but I have driven a bunch of trucks with that combination... for me.... they hauled just fine. mabey I'm not in a hurry to get down the road.... 🙃 jojo P.S. I like the 8LL... I would take it over a bunch of Mack tranny's... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479818 Share on other sites More sharing options...
0 Popular Post Mackpro Posted September 13, 2021 Popular Post Share Posted September 13, 2021 If the injection pump timing has not been checked in a long time I would get it checked and bumped up one degree over what it says on the valve cover. No more than 1.5 degrees over factory or you can get overheating issues. I remember checking pump timing on high mileage trucks and finding the timing can be as low as 2 degrees under factory due to slippage and gear wear . 3 Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479835 Share on other sites More sharing options...
0 mrsmackpaul Posted September 13, 2021 Share Posted September 13, 2021 I'm pretty thick as most here know, if your getting 25 pounds boost are you still making smoke at this boost ? If no smoke then it can only make more power with adding of more fuel, or at leasts my understanding of how the show works With 24.5 tyres and 4.17 gearing I doubt it will feel like a race car no matter what you do to the injector pump Paul 2 Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-479837 Share on other sites More sharing options...
0 EKCtransport Posted September 17, 2021 Author Share Posted September 17, 2021 Not getting any smoke at that boost. I’ll have to look into the timing. Thanks for the tips Quote Link to comment https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/#findComment-480066 Share on other sites More sharing options...
Question
EKCtransport
Hi guys I have 1994 Mack 688s with a 350 that has never been modified and not really happy with the power I’m getting. What do you recommend to increase my power without getting too out of hand and causing issues? Thank you
Link to comment
https://www.bigmacktrucks.com/topic/68061-1994-350-improvements/Share on other sites
9 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.