383 stroker vs. 400 short block dd question

[crabby]

I'm going to be putting together a direct drive boat a 13'6" cottonmouth with a 72" Q series prop, probably going to try slick bottom instead of poly this time, the boat will be as light as possible, pancake cage etc. My question is what motor do you guy's think will give me the best performance and longevity. I run a little dry ground not much.

 

[NorthWestFloridaBoy]

I don't know everything about this comparison but I can tell you the 400 is a siamese bore block, that can lead to cooling and longgevity problems. We need Waterthunder to chime in, he'll set ya straight on these two engines with all the important pros and cons. I vote for the 383. RedDwarf had a 383 with a Q series also and I seem to recall him being happy that setup, he has since moved up to a bad-a$$ gearbox and a Sensenich superwide.

 

[goldhunter_2]

do a search waterthunder address this same topic some time back.


My opinion is a 400 is a good motor but hard to find now the 383 is just a 350 that someone is trying to build up to compare with a 400. personally I would just start with the 400

 

[Waterthunder]

Hands down the best way to go is a 383. Here is why, their a little cheaper, the blocks are much stronger in the deck area and the main web area, out of the last 5 400 blocks I bought out of running vehicles 3 were cracked. They all pretty much crack in the deck area around the steam holes but their major problem which I have found to be VERY common is they crack near the lifter bores between number 2 and 4 cylinders. At the RPM's a DD runs at you can not possibly notice the HP difference! A good pump gas engine builder will make 1.5HP per cubic inch so around 6,000RPM your gonna see 25HP max difference between a 400 and a 383 and at 3,200 I doubt there is even a 12HP difference. However with the 383 you can run more timing and more cylinder pressure because of the smaller bore. You can make a 383 run just as good if not better then a 400 at 3,200RPM under a heavy load and the 383 will be much more reliable then the 400 can dream of. So to sum it up bigger bore motors are prone to detonating and the 400 blocks are rare, most cores are cracked and the deck surface doesn't hold gaskets as well. I prefer a 383 to a 400 99% of the time in airboat applications. If you run your boat hard and dry or run a DD go with a 383! If you know a good engine builder or if you can do it your self put a 3.875 ARM in it and build a 396! I have several 383's running on airboats with over ten years of reliable service!

 

[crabby]

Thank's Waterthunder, I was leaning towards the 383 also