n2ostroker
Petty Officer 2nd Class
- Joined
- Aug 9, 2008
- Messages
- 177
Re: 350 Engine advice
Re: 350 Engine advice
This is very true. I wish the boat was worth it and I had the money for some real headers. In the manifolds and risers there is no exhaust scavening happening. Especially if the through the hulls are in the water at all.
Anybody play with a wideband o2 or egt gauge on these for tuning? Or does the water play heck with the readings?
I may be totally wrong thinking the heads are restricting anything. I'll see more this weekend after removing the foil and adjusting the throttle linkage and carb. Also having some water thats doesn't beat me to death to test cruise and top end. Regardless the heads are being replaced this winter for a better design and better suited to the engine size. So the 305 heads performance is not of utmost importance. Same with the cam since I am unsure of what it is. I'll get it running good for now. I'll pop in some numbers on this thread as to results for this weekend for those interested.
If next spring I have some new found power and can max rpms fairly easy, then I can look forward to repropping. Who knows..
I mentioned lobe seperation just for the fact it might be a truck cam. I'm not having any reversion problems so it must not be too bad and probably around 112. I didn't assume that 305 had maxed the heads. More that with the current cam and head combination on a bigger higher compression motor I think it may be near that point and it may be holding back a few rpm. The 16% was more of an example of a direct change over if all parts were at max effeciency or power. Larger runner and same cam will have a different rpm range as well and could help and/or hurt power delivery.
As far as octane is concerned, I am fully aware I may not need as much as I have and too much can actually hurt power. This was just a precautionary action since I wasn't sure how the high compression would react in a constantly loaded environment and reading marine ping sounds different than in a car I wanted to be sure in case I didn't hear or recognize it. In a car I wouldn't have hesitated to drop in 93 and tune the timing if needed. I'm going to back off and just put 93 in this weekend to see how it acts as the booster mixed gas dilutes and runs through.
So to be more user/fuel friendly with a decent power boost I think the Vortecs are going to be the ticket from the great opinions about them. Probably go to the Comp 256 cam too. It's not too expensive and its been designed for a marine application.
It's not that I need a ton of power or speed. Just maybe maximize the potential of what I have within reason. I like playing with motors. cars, bikes, boats etc. That and learning from the guys who've been around a block that I haven't. Tuning a combo or building something and seeing the result of my work is what makes it fun. If it wasn't and I wanted something to hop in and go and not touch I'd go finance something and drop in the water.
Re: 350 Engine advice
This is very true. I wish the boat was worth it and I had the money for some real headers. In the manifolds and risers there is no exhaust scavening happening. Especially if the through the hulls are in the water at all.
Anybody play with a wideband o2 or egt gauge on these for tuning? Or does the water play heck with the readings?
I may be totally wrong thinking the heads are restricting anything. I'll see more this weekend after removing the foil and adjusting the throttle linkage and carb. Also having some water thats doesn't beat me to death to test cruise and top end. Regardless the heads are being replaced this winter for a better design and better suited to the engine size. So the 305 heads performance is not of utmost importance. Same with the cam since I am unsure of what it is. I'll get it running good for now. I'll pop in some numbers on this thread as to results for this weekend for those interested.
If next spring I have some new found power and can max rpms fairly easy, then I can look forward to repropping. Who knows..
I mentioned lobe seperation just for the fact it might be a truck cam. I'm not having any reversion problems so it must not be too bad and probably around 112. I didn't assume that 305 had maxed the heads. More that with the current cam and head combination on a bigger higher compression motor I think it may be near that point and it may be holding back a few rpm. The 16% was more of an example of a direct change over if all parts were at max effeciency or power. Larger runner and same cam will have a different rpm range as well and could help and/or hurt power delivery.
As far as octane is concerned, I am fully aware I may not need as much as I have and too much can actually hurt power. This was just a precautionary action since I wasn't sure how the high compression would react in a constantly loaded environment and reading marine ping sounds different than in a car I wanted to be sure in case I didn't hear or recognize it. In a car I wouldn't have hesitated to drop in 93 and tune the timing if needed. I'm going to back off and just put 93 in this weekend to see how it acts as the booster mixed gas dilutes and runs through.
So to be more user/fuel friendly with a decent power boost I think the Vortecs are going to be the ticket from the great opinions about them. Probably go to the Comp 256 cam too. It's not too expensive and its been designed for a marine application.
It's not that I need a ton of power or speed. Just maybe maximize the potential of what I have within reason. I like playing with motors. cars, bikes, boats etc. That and learning from the guys who've been around a block that I haven't. Tuning a combo or building something and seeing the result of my work is what makes it fun. If it wasn't and I wanted something to hop in and go and not touch I'd go finance something and drop in the water.
