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Old 03-16-2018, 06:18 AM
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Big Block Chevy Engine - Battle Of The Boost
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Old 03-18-2018, 11:39 AM
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Ok took my parts in for machining and the manifold landings on one of the 88 heads is pretty eaten up and since I'm looking at dropping $815 in labor in to them and another $340 to TRY and clean up the landings, I think it be better off looking for replacement heads.

So I'm thinking it's best to either pick up already done after market heads in the ball park of $1100 or get either a pair of Merlin 345 or iron eagle 345 and go through those instead.

IF I do the rebuild option, what's a better head the Merlin 345 or the iron eagle 345?

P.S. I can get a good set of 1-043b Merlin cores for $300?

Thanks

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Old 03-18-2018, 01:02 PM
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345's are way too big.
I'd look at these in the 320cc version. https://www.offshoreonly.com/classif...ds-o72091.html
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Old 03-18-2018, 01:36 PM
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Merlin iron heads dont flow much better than your heads in stock form. Griffs right, the 345s are too big.

the engine quest 320s griff put the link to, would work very well. The 308 iron eagle is a nice head as well.
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Old 03-18-2018, 02:29 PM
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Too big you say, I know the stocks are 320cc

So I understand, how this would affect the performance; if I go to a set of 345 with 2.25 valves with a crane 731 roller with 8-8.5:1 comp how would the motor run or what would change that you say there way to big?

Just trying to understand why.

Thanks

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Old 03-18-2018, 08:41 PM
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Originally Posted by Mohavvalley View Post
Too big you say, I know the stocks are 320cc

So I understand, how this would affect the performance; if I go to a set of 345 with 2.25 valves with a crane 731 roller with 8-8.5:1 comp how would the motor run or what would change that you say there way to big?

Just trying to understand why.

Thanks
Icdedppl and I have had a set of dart 345 iron eagles on the flow bench. They come with 2.30 valves. The EQ 320, flowed more cfm from .200, to .800 lift. Same bench, same fixture, same operator. Not a ton more, but again, larger port, larger valve, and flowing less

theres a good argument that one might opt for more airflow with a postive displacement blower , and not worry as much about port velocity . However, in this case, the bigger head doesnt flow more air, and doesnt have more velocity.

the dart 345 is a great head. Just wouldnt be my choice on a 454 build. Now, if you told me you wanted to turn 7000rpm with a 871-1071 on top, maybe.

downside to the larger port, larger valve, can also affect idle quality. Intake reversion is more pronounced with a larger valve, and slower moving port. Even though a larger valve can help pass more air into the cylinder, it also allows more air to be passed back up into the intake at idle.

the darts if i recall, are around 650 per head bare, the EQ around 450 per head bare. So, 1300 vs 900 for a set. 400 bucks is 400 bucks, and could be put towards valves , springs, etc. Both are great heads, and much better than a world products Merlin iron casting out of the box. At least the older merlins ive seen. The combustion chamber was horrible on them. Maybe they improved that in recent years , but the last set i saw, not so good
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Old 03-18-2018, 11:58 PM
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Duplicate

Last edited by Mohavvalley; 03-19-2018 at 09:35 AM.
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Old 03-19-2018, 12:03 AM
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I updated my post and maybe it got missed, the Merlin's are 1-043 castings, off a Mercury ( I think a 502). From my research there 345 but I'm not 100%

Here's the kicker I can be in the Merlin's $1,150 completely rebuilt with high performance valve job, Manley severe duty valves 2.25 intake and 1.88 exhaust and isky springs. So $1,000 less than the EQ'with parts, would you still go for the engine quests?
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Old 03-19-2018, 06:28 AM
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heres what the chamber looks like on my buddys merlins. Check out the blend from the valve seat to the chamber. The ridges in the throat from the seat were huge. Tonight i can post up what they flowed before and after some work.

thats a good buy though, if they have severe duty intakes with extreme duty exhaust. The extreme duty are inconel valves from manley, which you want with a marine supercharged build.
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Old 03-19-2018, 09:42 AM
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Yes if you could put up some numbers that would be great. Again I'm not shooting for big hp numbers just a solid strong runner.

If I went with a different cam or cam specs using the 1-043 (345?) Heads would that help with the reversion, maybe less duration?

Last edited by Mohavvalley; 03-19-2018 at 09:52 AM.
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