I ve got a 400 small block just the block and was wondering howmuch it gonna cost to get it machined. Everything done to the block machined wise and will probaly have them bore it out to 4.155" thats is 30 right.? And was wondering if any one has any parts combo bc i know eagle make one with crank pistins and rods., but Ive heard from alot of people put 350 cranks in it.
400 small block
- Thread starter 87ChooChoo3.73
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machine work on a 400 is the same as on a 350. i had my 350 bored .030 over, stroker clearenced, torque plated, align honed, cleaned, ring gap set, cam bearings and freeze plugs installed for $500
what are your plans for the engine? if you want high RPM's, you could use a 350 crank to de-stroke it to about 374ci. but only bother if you really need the RPM's. otherwise you always want more displacement.
i'd double check with a good piston manufacturer, but i'd use 6in rods as long as they don't interfere with the rings.
parts are easy, it's a relatively common motor. and many 350 parts will swap over including vortec heads.. just make sure that any heads you use have the steam holes drilled out. and you have to use a 400 balancer and flexplate/flywheel due to the different balancing method. do NOT skip having the rotating assembly balanced!! any engine should have it done, but on higher stroke/power engines it's a must and well worth the expense. and if you use a stock oil pan i believe it must be from a 400.
what are your plans for the engine? if you want high RPM's, you could use a 350 crank to de-stroke it to about 374ci. but only bother if you really need the RPM's. otherwise you always want more displacement.
i'd double check with a good piston manufacturer, but i'd use 6in rods as long as they don't interfere with the rings.
parts are easy, it's a relatively common motor. and many 350 parts will swap over including vortec heads.. just make sure that any heads you use have the steam holes drilled out. and you have to use a 400 balancer and flexplate/flywheel due to the different balancing method. do NOT skip having the rotating assembly balanced!! any engine should have it done, but on higher stroke/power engines it's a must and well worth the expense. and if you use a stock oil pan i believe it must be from a 400.
and since the 400 is a 2-bolt main block i HIGHLY recommend align honing it and you pretty much have to use ARP quality main studs.
A 377 would be interesting ( 350 crank), but so would a destroker 350(?) with a 327 crank in a 400 block and really long rods. You would get a great rod/stroke ratio and the ability to rev. Hot Rod built one back in the 90's using Ford 300 inline six rods. It is worth a read, since it idled smoothly, made 400+hp, ran on 87 octane gas and had 11:1 compression!!! Here's a link to a scanned copy of the article I just happened to have bookmarked. http://www.purplesagetradingpost.com/sumner/techinfo/350 chevy engine.html
Yeah, for sure sounds like you got some good ideas. Didn't the 400 come in 2 and 4 bolt? But a down stroker...do it. Let us know what you decide, post pic's, lotsa pic's. Good luck
One of my all time favorite engines in a magazine was a Chevy 302 with a blower that got really good gas mileage. I would love to build a small displacement Gen I SBC with twin turbos ( sub 300ci!!) that would minimize the fuel consumption under part throttle, but still move enough air and fuel under boost to make lots of power. The only drawback is that a small bore in a 2 valve engine limits your air flow. There is an advantage to a small bore though, and that is that the amount of space occupied at TDC is much smaller than a large bore engine, thus permitting much more complete combustion, and lower NOX emissions.
The downside to a small displacement pushrod engine is that there is an excess amount of weight in the valvetrain. Plus, the huge distance from the cam to the valve means that those parts can move around a bit. So, you lose some accuracy, and the inertial forces will lead to valve float without very strong springs. But, the strong springs will impart wear of their own on the valvetrain, reducing reliability. So, you run up against a limit of reliability in a street engine if you try to pull real revs with it. Either you would need a super light valvetrain, or a DOHC conversion to reliably do it in a street car.
The downside to a small displacement pushrod engine is that there is an excess amount of weight in the valvetrain. Plus, the huge distance from the cam to the valve means that those parts can move around a bit. So, you lose some accuracy, and the inertial forces will lead to valve float without very strong springs. But, the strong springs will impart wear of their own on the valvetrain, reducing reliability. So, you run up against a limit of reliability in a street engine if you try to pull real revs with it. Either you would need a super light valvetrain, or a DOHC conversion to reliably do it in a street car.
If this is for a regular weight street car then I am with Mega keep the cubes. More torque at lower rpms will make it more enjoyable to drive and less likley to require maintenence, converter, gear, cam, compression, etc. It will generally be as fast and not require you to spin the snot out of it to make it go. More torque at a lower rpm in a regular weight street car will generally offset the larger displacement for about the same fuel consumption. You can get a strong inexpensive balanced rotating package for cheap with one of these. Consisting of a drop in aftermarket crank with the longer than stock rods & matched 30 or 40 over pistons. No fuss no muss drop in & go. Add some relatively inexpensive vortec heads & headers and your good to go with a strong 406/408 that can breath deep and still rev if & when you want to.
2 cents. A rod to stroke ratio of 1.7-1 has long been considered & generally researched as an ideal ratio for a strong street engine that does not spend all its time at high rpms. For a race motor that spends most of its run time at 7,000+ rpms a higher say 1.9-1 or greater can be worth the hassel & the cost. For street anything over 1.5-1 is still going to handle say 6,000 rpm fine and not cost you excessive power or wear. AFR heads are sweet to but when you are actually writeing the check for your street car the Vortecs start to look mighty appealing.
2 cents. A rod to stroke ratio of 1.7-1 has long been considered & generally researched as an ideal ratio for a strong street engine that does not spend all its time at high rpms. For a race motor that spends most of its run time at 7,000+ rpms a higher say 1.9-1 or greater can be worth the hassel & the cost. For street anything over 1.5-1 is still going to handle say 6,000 rpm fine and not cost you excessive power or wear. AFR heads are sweet to but when you are actually writeing the check for your street car the Vortecs start to look mighty appealing.
Sounds great thanks for all the ideas. now all i have to do is wait i need to sell a few things i have then im gonna start.Thanks again
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