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SB 05-20-2020 02:04 PM

525EFI cam is Getting up their in duration. 236 at .050, therefore in a 454 you’ll want near 10:1 compression.

Also, the LSA is a little wide at 114. 112 would fare better power and rpm band wise.

Rookie 05-20-2020 08:39 PM


Originally Posted by picca00 (Post 4739834)
Rookie are you running dry exhaust? What’s that max lift you can get away with staying with reasonable compression?

Stainless Marine dry to the tip will be used with the above mentioned build.
My other built 454's currently have 235°/241° 0.684"/0.665" (rocker 1.8,1.75) LSA 113, 9.0:1 with custom Dart Pro1 heads and CMI E-Top that are dry 3/4 to the transom. These use to have 252°/264° 0.668"/0.668" @ 9.7:1 with the dry to the tip Stainless Marine exhaust.

KRAUSMOTORSPORTS 05-21-2020 12:30 PM


Originally Posted by picca00 (Post 4739903)
what heads did you use and what’s the approx hp?

9.5:1 454 GEN VI Using Merlin 1043-C heads. 310CC, 119cc, 2.300 Intakes, 1,88 Exhaust Heavy but in marine world I was building for longevity with Matching Merlin intake with Brass Water Jackets. 800 Holley from HP500, 168731 Crane Cam 226/236 .587 / .610 112*
I'm guessing around 500hp ish. I run 93 in all my engines so I tend to lean towards higher compression then most. Contemplating on taking it to the dyno just to proove itslef. I'm may be selling this engine soon. If I did run this I have Stellings Full Dry Exhaust to Tip exhaust.


Originally Posted by SB (Post 4739905)
The 731 is a tad smaller than the 500EFI cam. (226 vs 230 int duration at .050”)
Still a good choice for many 454/502 builds.

Agreed, I built this engine with possible intent of selling so didn't want to go too big. For reliability I like the Smaller 500EFI or 731 for 454's and 741 or 525EFI's for 502+ Ci.

picca00 05-21-2020 07:23 PM

Ok thanks guys, I figured the 112 would be better, but in general if I go with the bigger 525 cam, I will just need a little more compression and spin more rpms? I only run 93 octane so 9.5-9.7 compression should be ok and possibly still make the power just under 6k?

hogie roll 05-22-2020 06:45 AM


Originally Posted by picca00 (Post 4740148)
Ok thanks guys, I figured the 112 would be better, but in general if I go with the bigger 525 cam, I will just need a little more compression and spin more rpms? I only run 93 octane so 9.5-9.7 compression should be ok and possibly still make the power just under 6k?

What intake?

picca00 05-22-2020 07:13 PM

High rise intake most likely, I don’t know if a air gap would be enough...

hogie roll 05-23-2020 06:46 AM


Originally Posted by picca00 (Post 4740284)
High rise intake most likely, I don’t know if a air gap would be enough...

The air gap is probably the best intake up 600ish. Which you may be flirting with depending on how much cam you use.

What boat is those?

KRAUSMOTORSPORTS 05-23-2020 01:40 PM


Originally Posted by hogie roll (Post 4740323)
The air gap is probably the best intake up 600ish. Which you may be flirting with depending on how much cam you use.

What boat is those?

A single plane like Team G, Dart, Merline would perform better up top. But a dual plane would be better controlled at the docs IMO. I love the air gap. Just wished they had a marine version for those of us running raw water. Even though we have had engines with standard Intakes last almost 20 years! We're in brackish waters.

picca00 05-23-2020 04:41 PM


Originally Posted by hogie roll (Post 4740323)
The air gap is probably the best intake up 600ish. Which you may be flirting with depending on how much cam you use.

What boat is those?

I’m really leaning towards the 525efi cam if I can’t find something on a 112... it’s for 1979 glastron Carlson cv23 that I’m restoring... floor stringers, transom all done, onto the test rigging phase and a lot of custom work to get want I want...

picca00 05-24-2020 07:24 PM

So any more opinions on me putting the 525 efi cam in my 468 build? I thinks that’s my pick...
thanks for the input


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