I been thinking about something now that the warm weather is here. My Engines are stock 454/420's. Last summer I had to pull the heads from the port engine, due to leaky valves. I sent the heads in, and while it was apart I thought I would replace the cam and lifters. My builder said he uses a cam company that is a replacement for the orginal 420 cam. So I went with that one, which is a Elgin grind. I am trying to find the specs.

The one thing I noticed when I got it all together, and ran the boat, the port motor(new cam) had a slightly lopier idle. The stock 420 idled very smooth in gear. But the port motor seemed to have more "cam". On top the port motor would out pull the stocker by about 150 rpms or so.

My question is, if the cams have the same lift and duration numbers, but one is a 114LSA and 110LSA, would this explain my symptom? I am not sure if the Elgin cam is a 110LSA yet, I am trying to look up on the web but they dont list their cam specs online. If this is the case, I may yank the stock cam out and go with another new Elgin cam. I like the sound better and it seems to pull a little harder. Thanks!

The 110 LSA will give better top end as there is more overlap. EG the intake opens while the exaust is still open. The reason for this is to use the momentum of the gasses blasting out the well designed exaust. This gives the intake charge a strong signal and a bit of a head start down the intake runner them, bam, you shut the exaust and the intake charge really gets a head of steam on. The down side is that at low rpm it dosnt work as well so a loapy idle.
Be warned though that if you have wet exaust then a 110 LSA cam will cause water to be sucked back up the exaust into the exaust port.
Hope this helps.
Jas

couldnt you also have a timing issue that could cause this.
same cams but installed at a different degree....or....
even your initial timing being different by a couple degrees??

just a thought

b70

The good thing is my exhaust doesnt add water to the mix until about 20 inches back from the riser flange