Re: Upgraded engine lost speed any help?
 

Thanks for the input SB,
I am sure the cam went flat because of oil breakdown. I was using the stock 330 oil cooler which is about the size of a beer bottle. I am now using a 3" EMI oil/ps cooler combo. I always us Castrol GTX strait 30 or 40. I used to use 40 but since I put on the oil cooler on the oil pressure is the same with 30. I ported & pollished the heads, had larger valves & hardend seats installed, also had them milled down slightly to get the combution chamber to 110cc. Before I bought them I found some info about them on this website.

http://www.mopar1.us/headflow.html

Thanks,
Jeff

Re: Upgraded engine lost speed any help?
 

By chance what ratio roller rockers did you use and which cranes? Also what size pushrods did you change to with the new cam?

Re: Upgraded engine lost speed any help?
 

3 flat tappet wear threads from the other site:

http://www.speedwake.com/upload/show...lat+tappet+oil

http://www.speedwake.com/upload/show...lat+tappet+oil

http://www.speedwake.com/upload/show...lat+tappet+oil

Re: Upgraded engine lost speed any help?
 

Comp Cams 1.7 Roller Rockers, oversized pushrods stock length.

Re: Upgraded engine lost speed any help?
 

OK
I was not worried about any mechanical problem till now. I still have the filters from my last 3 changes. I am so paranoid after 3 engine failures in 3 years that I changed the oil 3 times in 30 hours of use. I may open the filters up just to make sure.

Re: Upgraded engine lost speed any help?
 

Some of you recomended I switch props, thinking that I am not in the correct range for the engine to reach peak RPM. I just got the boat out of storage and installed a 23 pitch 4 blade Hydromodive. I will test it tomorow and let you know the results.
Thanks for everyones input.
Jeff

Re: Upgraded engine lost speed any help?
 

This may be a dumb question, have you varified the spark plug wiring with the timing order? I drove around for a month with 2 wires reversed. Twin engines, it ran OK but one was down on power, Daa. You may want to pull the plugs and see if they are reading the same. Someone may have accidently broken one of your spark plug wires.

Re: Upgraded engine lost speed any help?
 

I assembled all of the accessories myself. I am sure the wires are not reversed I alway double check. I may pull the plugs and take look just to see if they look different. I also thought I might put my old bosch plugs back in and see if that makes a difference.

Re: Upgraded engine lost speed any help?
 

I tried the prop yesterday. The Hydrodive prop did not work well at all. I could not get enough bow lift, porpoised all over the place. If I aired out the prop I could get the RPM to 4800 but lost speed. I put my mirage 25 back on today. I am pretty sure at this point it is the cam that made the difference. Thats what I get for listening to the Tech Line for advice. I should have bucked up and went with a bigger roller cam.

Re: Upgraded engine lost speed any help?
 

jeffswav -

I checked my Holley catalog and did not see an MPI intake for the peanut port heads. Do you have one or is it for the large oval port heads ?

Where your large oval ports modified correctly for the larger valve installed ? Meaning - chamber, bowl, and throat porting ? Not modifying the chamber and bowls when installing larger valves can actually decrease airflow. Although I have not dealt with closed or semi-opne chambers, however I would think that larger valves would come closer to the as cast chamber walls and cut some airflow. Some relieving would be necessary. Again, check with head person since I have no experience with these heads.