What engine do I have? New member

[Barney0024]

I am new here and I have to say that this forum is great! So many neat ideas and really nice looking boats. I have a 1983 Supra Rider that I bought from a friend about two months ago. It is restored from the hull up and was repowered when restored. It has 250 hours on it. It had been in storage for the better part of 10 years unused with the exception of one weekend 3 years ago. Boat runs great and is a ton of fun! I am trying to figure out which 454 I have. Pretty sure it's the HO. I want to make sure it's propped correctly. It's a pcm engine with a sea maxx tag on the valve cover, model#slnhfl20d, serial# 195153. It has a velvet drive 1:1. I have contacted PCM and at first I was told they had no info. They poked around and sent me an owners manual. I just want to make sure I am reading the model # correctly so I have the right engine code. Any help would be awesome!

I will get some pictures up soon!

[Cusefan78]

That is not a pcm motor. If it was pcm it would start with a p. sea maxx starts with a s. it's a left hand rotation 454 based on the 3rd digit. It's suppose to be the 4th but it's push back cause of fresh water cooling. The numbers after the engine are wrong. Look again and I attached the chart to decipher it. image.jpg

[Barney0024]

I assumed seamaxx was a pcm brand. I checked the numbers and what I posted is what is there. I am attaching a picture. I also wondered about this. So according to the engine code "N", my WOT rpm range is 4800-5200? Does this seem right? I finally got a chance to run it wide open on Sunday. I hit 42 at 4500 rpm. Prop is 14x14.
image.jpg

[Barney0024]

Her is another picture. As you can see it says pcm on the manifold
image.jpg

[SquamInboards]

Her is another picture. As you can see it says pcm on the manifold
image.jpg

What are the odds that there's another marine engine company in Little Mountain, SC that someone later bolted PCM manifolds to? If you google PCM SeaMaxx it seems like it was something that existed in the late 90's... Maybe PCM bought out SeaMaxx and then phased out the name??? Or SeaMaxx was using PCM manifolds??