Flat top pistons
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Joined: Sep 2001
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A 400 (no M) really wakes up when the compression is increased. It was a real good engine when introduced in 1971 and everybody wanted one. Unfortunately they ruined it the next year.
High Performance Options for the 351M/400 Engine by Dave Resch
High Performance Options for the 351M/400 Engine by Dave Resch
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From: western montana
TMI (sponser) sells the Badger for 170 or so. Not sure what he has in stock. SOmetimes you can find them for a bit less but they are not always abundant and tim has a lot of knowledge to go along with his product. Search this forum and you will find a plethora of info...
There a 3 ways to legitimately bump compression which is what the 400 needs to make it a legitimate contender with the best of motors- which it is. You can go with stock pistons and heads off australian 351b motors- cost 4-$500 or more to your door
but them you can buy special made kb pistons from tmi that provide incredible quench and 9.5:1 cr that will run on 87pump- with performer intake and carb and you will get an easy 440 ft lbs and 340hp with a rv type build.
You can also get the badger pistons or kb flattop pistons for a cleveland and have them bushed- similar result.
Next is to deck the block and heads etc....more expensive and limits use imo.
There a 3 ways to legitimately bump compression which is what the 400 needs to make it a legitimate contender with the best of motors- which it is. You can go with stock pistons and heads off australian 351b motors- cost 4-$500 or more to your door
but them you can buy special made kb pistons from tmi that provide incredible quench and 9.5:1 cr that will run on 87pump- with performer intake and carb and you will get an easy 440 ft lbs and 340hp with a rv type build.
You can also get the badger pistons or kb flattop pistons for a cleveland and have them bushed- similar result.
Next is to deck the block and heads etc....more expensive and limits use imo.
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Brett Foote
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Joined: Dec 2002
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From: chicago burbs
gotta wonder if the current fuel blend is enough to help a 9:1 engine pass? it's been a long time and a lot of changes in the fuel since they "smogged" the 400 to death. i suspect the doctors lost that patient unnecessarily. new vehicles are coming out at 10:1 and higher under much more stringent standards, granted they are computer controlled but there should be a happy medium for the tune-up that'll get you through the lane
Last edited by grclark351; Jun 10, 2006 at 09:57 PM.
Tuned
Joined: Jul 2003
Posts: 455
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From: Berkeley
fwiw: i'm running ~8.7:1 static compression and have had no problems passing smog in CA. then again, my '82 E350 is considerd 'heavy duty' and got a break emissions-wise. latest smog cert in my gallery.
Cargo Master
Joined: Oct 2020
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Those pistons look like the Autotech/Racetech pistons. They are about the most reasonably priced custom pistons available right now. The set that I got from them a couple of months ago took about 8 weeks to arrive. It'll probably take a heck of a dish to keep your compression below about 8.5:1. I'd have to figure it out but I bet that you'll need about 25cc or so.
Laughing Gas
Joined: Sep 2013
Posts: 1,118
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From: North Idaho
I want to say a flat top piston in a 400 is something like 12:1 compression. I.E. not street friendly. This is why TMeyer has been so successful with his line of pistons.
AutoTech / RaceTech will make you a custom forged dished piston in whatever compression you like for a reasonable price.
AutoTech / RaceTech will make you a custom forged dished piston in whatever compression you like for a reasonable price.
Hotshot
Joined: Jul 2020
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From: Near Salt Lake City
A 400 (no M) really wakes up when the compression is increased. It was a real good engine when introduced in 1971 and everybody wanted one. Unfortunately they ruined it the next year.
High Performance Options for the 351M/400 Engine by Dave Resch
High Performance Options for the 351M/400 Engine by Dave Resch
It needed a bit more compression too