Marine 273 build
Lots of great feedback- thanks!
Toolmanmike, yes I ready your entire build last week- and I believe we are shooting for something similar with our prospective 273 builds. I recall you thinking that you were shooting for ~300hp? Id be tickled with 250-275hp, all in by say 5200rpm. Could you give me some more info on what you did for heads?
Reverse rotation in single engine inboards
good question. As others have mentioned, early marine engines utilized car engines were mounted flywheel forward, driving the transmission via the crank. Propellors rotated right (as viewed from the rear), and drivers were placed on the right (starboard) so that their weight counteracted the torque of the propeller. As the starboard helm became the industry standard, reverse rotation engines were required to turn RH props when they spun the engine back forwards and drove the transmission via the flywheel. It is important to get the boat riding as level as possible with just the driver aboard, as it evens out the ski wake. Correct Craft still utilizes RH props on their direct drive inboards- though as of 89, theyve been able to use LH (standard rotation) engines to achieve this (the transmission reverses the direction of rotation). Engines were almost exclusively reverse rotation through 88 though.
69 Cuda, you are correct- the 340 HO (reverse rotation) cam that I mentioned above was believed to have been built by Camcraft and sold under various other brands (Clevite, etc). Theyre NLA but we have access to a few of them. Funny you mention lake Mahopac- my sisters 69 Correct Craft came from that lake (though it is Ford powered).
Youre correct that the marine intake has a built in wedge. When going to an aftermarket intake, its common to install a separate wedge spacer, though the AFB/Eddy is more susceptible to the angle change than a Holley. We have successfully installed the LD4B intake and fit it under the hood- so that is the way we plan to go for these new builds unless the RPM is known to be similar in height. No need to go low rise. We do need to make modifications to the cooling passages to an aftermarket/automotive style intake, but that is something we are prepared for.
So back to one of my original questions- how do these parts look as far as hp goes?
273 +.030 with factory replacement 10.5 domed pistons from Egge
Cam: 429/444 (210-220) rev rotation marine cam
Ported 273 heads (2465315)
Edelbrock D4B intake
I suppose it really matters how good the port job is on the heads? Can someone give me a range? 235hp with minimal port work? More? Less? Just curious how much time (or money) needs to be spent here.
As we all all like pictures, here is the very nice 273 that was installed in the blue boat pictured above (prior to being replaced by a 340). It was dressed up like marine version of the Commando. Oh, and a quick video of our splash test last year
a scorching 46mph, ha.
[ame]http://youtu.be/U3E4hQB_tpY[/ame]
