406 vs. 355...Which to build?
Thread Starter
Instructor
Joined: May 2001
Posts: 136
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From: Hillsborough North Carolina
406 vs. 355...Which to build?
Hello everyone,
I have a question concerning my latest project. I have recently bought a 1972 Vette which, need tons of work( it sat in someones back yard for almost 10 years). The frame and birdcage all appear good and relatively rust free( minor surgface rust). Anyway, I have the option of building either a 406 or a 355 as I have both engines setting in the garage. Either would be built as a relatively mild street engine. My concern is about overheating issues. I have read in different places that, the 406 may have some overheating problems. I know that Vettes also, have issues concerning getting heat out of the engine compartment. So, are any of you running a 406 on the street? If so, any problems? Things I should look out for?
Any advise would be greatly appreciated.
Mike
I have a question concerning my latest project. I have recently bought a 1972 Vette which, need tons of work( it sat in someones back yard for almost 10 years). The frame and birdcage all appear good and relatively rust free( minor surgface rust). Anyway, I have the option of building either a 406 or a 355 as I have both engines setting in the garage. Either would be built as a relatively mild street engine. My concern is about overheating issues. I have read in different places that, the 406 may have some overheating problems. I know that Vettes also, have issues concerning getting heat out of the engine compartment. So, are any of you running a 406 on the street? If so, any problems? Things I should look out for?
Any advise would be greatly appreciated.
Mike
Le Mans Master
Joined: Feb 1999
Posts: 5,877
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From: Park Ridge IL
Re: 406 vs. 355...Which to build? (piratemike)
I wouldn't worry about oveheating. There are plenty of high performance 400 based engines in C3's here. Build the 406 - like the saying goes, there's no substitute for cubic inches (except cubic money and/or boost ;) ).
The problems with overheating 400 was mostly due to people putting 350 heads on them and not drilling the steam holes or running the appropriate matching gaskets.
However, I don't have steam holes and my engine doesn't come anywhere near overheating. Actually, if I have the electric fans turned on, it won't get hotter than about 165, which is too cold in my opinion.
I actually tapped and plugged the large coolant holes on the deck surface and drilled them smaller. I also run a Stewart Stage 4 aluminum water pump with higher pressure and volume, along with external cooling lines routed to the heads inbetween the 2 middle siamesed exhaust ports. This is mostly an 18* heads thing, but it can be applied to any head. The combination of plugging the large deck holes and the higher flow water pump increases the coolant pressure in the block, preventing the steam pockets the steam holes are drilled for.
The problems with overheating 400 was mostly due to people putting 350 heads on them and not drilling the steam holes or running the appropriate matching gaskets.
However, I don't have steam holes and my engine doesn't come anywhere near overheating. Actually, if I have the electric fans turned on, it won't get hotter than about 165, which is too cold in my opinion.
I actually tapped and plugged the large coolant holes on the deck surface and drilled them smaller. I also run a Stewart Stage 4 aluminum water pump with higher pressure and volume, along with external cooling lines routed to the heads inbetween the 2 middle siamesed exhaust ports. This is mostly an 18* heads thing, but it can be applied to any head. The combination of plugging the large deck holes and the higher flow water pump increases the coolant pressure in the block, preventing the steam pockets the steam holes are drilled for.
Advanced
Joined: Apr 2003
Posts: 54
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From: CT
Re: 406 vs. 355...Which to build? (The Dude)
406......Basically a stroke of a 350 with a big bore. Some people even destroke the 400 to a 377 to get high rpm's out of it while having a nice big bore to work with. :cool:
Melting Slicks
Joined: Sep 2000
Posts: 3,099
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From: PITTSBURGH PA
Cruise-In IV Veteran
Cruise-In V Veteran
Re: 406 vs. 355...Which to build? (patsnitrovette)
you do not need to drill the heads for the 400 either just make sure you hav enough rad and you wiil not have any problems i build all 400s with out steam holes :cool: :cheers:
Safety Car
Joined: Feb 1999
Posts: 3,631
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From: Fountain Hills AZ
Re: 406 vs. 355...Which to build? (piratemike)
Another vote for the 406. The extra costs involved will still result in some of the cheapest hp you can buy. Also, that extra hp will be throughout the usefull rpm range rather than just at the top.
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Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
Re: 406 vs. 355...Which to build? (The Money Pit)
My 406 is not in the car yet and my cost tally is @ $6500, having bought the block and crank for $200 and using my 1985 distributor and fuel injectors, the rest being bought new parts and new ARP bolts.
I did buy the miniram for $600, would have been $1250, hooker 2151-1's for $350 would have been $450, BBK 58 MM TB for $220 would have been $320.
So if you build a new motor with all new parts I could see @$8500
Now if you have not passed out, I would build a 406 and if you have more money to spend a 412 or 421 etc. :party:
I did buy the miniram for $600, would have been $1250, hooker 2151-1's for $350 would have been $450, BBK 58 MM TB for $220 would have been $320.
So if you build a new motor with all new parts I could see @$8500
Now if you have not passed out, I would build a 406 and if you have more money to spend a 412 or 421 etc. :party:
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: 406 vs. 355...Which to build? (ld85)
Id85, YES, engines are expensive. But tell us, how much MORE is this 406 costing than the 355, as the question posed? I'll bet that after the $200.00 block and crank, the 406 isn't much more than the 355. YES??? Good luck, and...
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Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Re: 406 vs. 355...Which to build? (CFI-EFI)
Id85, YES, engines are expensive. But tell us, how much MORE is this 406 costing than the 355, as the question posed? I'll bet that after the $200.00 block and crank, the 406 isn't much more than the 355. YES??? Good luck, and...
RACE ON!!!
RACE ON!!!
Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
Re: 406 vs. 355...Which to build? (Vetterodder)
Id85, YES, engines are expensive. But tell us, how much MORE is this 406 costing than the 355, as the question posed? I'll bet that after the $200.00 block and crank, the 406 isn't much more than the 355. YES??? Good luck, and...
RACE ON!!!
That was my point also. While some of the 406 pieces may be a little more expensive, they're not much more expensive than parts for a 355. A lot of the costs involved for heads, intake, cam, etc. are the same either way. You can't reuse a balancer or flywheel from a 350 but the added cost there is still a bargain for the extra power you get from the extra cubes.
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That was my point also. While some of the 406 pieces may be a little more expensive, they're not much more expensive than parts for a 355. A lot of the costs involved for heads, intake, cam, etc. are the same either way. You can't reuse a balancer or flywheel from a 350 but the added cost there is still a bargain for the extra power you get from the extra cubes.
Oh yeah, a new radiator for the 406 if you want to be safe!
[Modified by ld85, 3:47 PM 4/20/2003]
Burning Brakes
Joined: Jan 2002
Posts: 1,206
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From: Redondo Beach CA
C2 of Year Finalist (performance mods) 2019
Re: 406 vs. 355...Which to build? (piratemike)
You said " Either would be built as a relatively mild street engine. " which means there is no reason not to build the 406. If you said you wanted lots of top end power, then I might recommend the 355, but you can build a torque monster 406 that has great idle and will be perfect for the street. A 406 of equivalent power to a 355 will create the same amount of heat, so if your radiator can't handle the 406, it would not have been able to handle a similarly built 355...
Melting Slicks
Joined: Sep 2000
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From: PITTSBURGH PA
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Re: 406 vs. 355...Which to build? (bcwaller)
the 406 will not produce any more heat than a equivalent 350 but if you start pushing some big hp numbers through it either run will run hotter up untill last year i was runnig a stock rad in my stout 406 ran on the hotter side about 200-210 inthe really hot summer with out ac and 230-240 with ac all i put in was a be cool and now have a hard time getting it up to 160+ a mild 406 should be fine with a stock rad tho :cheers:
Race Director
Joined: Sep 2002
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From: San Diego - Deep Within The State of CONFUSION!
Re: 406 vs. 355...Which to build? (CORKVETTE1)
I used a standard 383 setup but for two things: It is a 4-bolt main block and it is bored .040 rather than .030 so the engine is actually about 388CID. I used an Eagle stroker kit with forged crank and 6" rods.
It has all the torque It needs and winds up to 5500 all day long. DD2000 shows it to have 350HP and 420 Foot pounds of torque.
The Dynojet shows at the wheels 275 HP and 300 Foot Pounds. Very mild idle (Here's the cam card: http://dab7.cranecams.com/SpecCard/D....asp?PN=113942 )
It has all the torque It needs and winds up to 5500 all day long. DD2000 shows it to have 350HP and 420 Foot pounds of torque.
The Dynojet shows at the wheels 275 HP and 300 Foot Pounds. Very mild idle (Here's the cam card: http://dab7.cranecams.com/SpecCard/D....asp?PN=113942 )
