454 Mag questions

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03-13-2007, 09:37 PM

#11

cuda

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Quote:

Originally Posted by glassdave

Thanks, great info guys. i am not looking to get to deep into these engines as i have another pair i may put in next season. So far i am pretty set on the AirGap intake and bigger cam (anybody got a part # thay can recomend?) also thinking about Dana Torque flow exhaust. Would i benafit from 1.7 roller rockers over 1.5's? what is the up and down side of the 1.7 rockers?

Comp 292 H is what's in mine. It was originally a 454/420. Idles great, sounds and runs fantastic. It also has Merlin intakes, 10:1 compression, 800 Holleys (I think), and Gil exhaust.

http://www.zippyvideos.com/683233795...5-05_008/*cuda

03-14-2007, 05:25 AM

#12

Payton

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Quote:

Originally Posted by glassdave

Would i benafit from 1.7 roller rockers over 1.5's? what is the up and down side of the 1.7 rockers?

If I am not mistaken the 365 already has the 1.7 rockers. some guys are going to the 1.8 s on the intake side. The small block use the 1.5s

03-14-2007, 08:03 AM

#13

Croozin2

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Quote:

Originally Posted by Payton

The Crane 241 is a slight improvemnt over the stock Merc 420 cam. Mine runs very strong with a set of Gold roller rockers the 241 cam Air Gap or similar intake and an 800 Holley. The stock alum intake with a little more spacer and the stock 750cfm Qjet carb is still a very good combo with that cam.Also some better than stock exhaust.

My stock springs were fine and good enough for this cam.

I went a bit deeper into mine than you are planning to go but I had some previous salt water damage that needed to be adressed ASAP. Wound up with 509 and 513 HP repectively out of mine. As was stated earlier, some minor head cleanup, 2.30 valves, Crane Gold Roller Rockers, bumped the compression from 8.75 to 9.5, had a cam ground by Cam Motion single pattern hyd .561" lift with 236 @ .050, crane ignition and EMI exhaust and used the stock aluminum intake and Q-Jet but with a 1" spacer and a lot of finessing with the carbs. I'm an old Super Stock racer so I enjoy playing with combinations that everyone says "won't work".

I gained about 8mph on my Formula 311 but needed much more prop. Boat ran 72 @ 5600 with 23 pitch Mirages. Could have easily made 75mph+ with a little more wheel. I think the point to everyone's post here is that the bottom end of the old mags is bulletproof. They will take a lot more than the 365hp that came stock.

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03-14-2007, 10:47 AM

#14

KAAMA

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Quote:

Originally Posted by Griff

I also think you would need to add exhaust to see real gains and that adds a lot of $$$. I would say if you're not ready to spend 3k per engine, then leave them alone

Aye, Aye to that!

03-14-2007, 06:09 PM

#15

Croozin2

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Originally Posted by KAAMA

Aye, Aye to that!

I second that motion!! If you aren't willing to spend the $$$ on exhaust, Fuggit about it!!!

03-14-2007, 06:28 PM

#16

jeff1000man

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Merlin ovals, edelbrock intake, Crane rockers, 800 marine holleys.

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03-14-2007, 11:27 PM

#17

glassdave

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Quote:

Originally Posted by Payton

If I am not mistaken the 365 already has the 1.7 rockers. some guys are going to the 1.8 s on the intake side. The small block use the 1.5s

yep, my mistake for some reason i forgot the DDC's were 1.7's

pretty sure i am going with Dana torque flow manifolds when i do the mods. i have been looking for a reason to get them. you guys are right the improvments wont be fully realized without good breathing exhaust. its not really a money issue but what i plan on in the future, the 525's i have lined up have e tops on them already but i am thinking they wont find their way into this boat anyway. most likely sit on them for a future project.

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Last edited by glassdave; 03-14-2007 at 11:31 PM.

03-14-2007, 11:35 PM

#18

OPA

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dave i might have what you need, i just went from gil exaust to stainless marine, i have 3 sets of gils

03-15-2007, 07:51 PM

#19

pkspx

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Dave, Talk to Dean Gellner, (MrHorsepower1 on OSO), in Cleveland and he can get parts for you to wake that thing up. A good combo like heads, cams and intake manifold will make a difference. Dean has the experience with the 454 from Dyno pulls so he knows a decent amount of hp mods in mind for you. When I had Gellner upgrade my original 454 with just head work and a intake manifold, I was pushing close to 480hp.

Last edited by pkspx; 03-15-2007 at 07:54 PM.