sick240

ok not sure what i want to build, stroke the 350 i have to a 383 or buy a 400 and build it. what do yall think would be my best bet?

its going in a 2580 lbs 73 240z (the weight is with the 350) the car is a street car on pump gas and would like to keep it that way.

thank for your time.

Chevy_Stroke

a friend of mine had a 78 280z with a completely stock 400 except the cam, intake & carb and it ran low 12s and the timing wasn't set right. if you goin to spray it id say 383. plus parts are cheaper for the 350.

rtk434

iTrader: (1)

I would go with the 383. You already have the 350 block and finding a good 400 block is getting harder to do. Plus the 350 blocks hold up better in most cases. You're only leaving a few cubic inches on the table anyway. It shouldn't be hard to build a pump gas 383 that will put a car that light into a differant time zone.

sick240

yes the 509 400 blocks are getting rare, and i will be spraying it. also cost will play a part.

ZONES89RS

iTrader: (25)

Well, i have a 400 small block that is going in my 89 one day, but hell, if the cubes matters use the 396 stroker kit, i am sure it is worth it if you already have the block. I think that would be the answer if you want cloer to 400 ci. But a 383 is prooven time and time again to take punishment.

Chevy406

iTrader: (12)

Spoken by someone with a ton of experience no doubt

Certainly use the 350 block you already have, but don't be afraid of a 400. My first 406 had stock cast crank (.030/.030) with 5.565" rods and forged pistons. It held up just fine to nitrous.

Sharpe

iTrader: (7)

Had a 383 and loved it, but I'd do a 406 if given the chance to do it over.

Dragkid1917

iTrader: (2)

My dads got a 388 in his 64'chevelle, Im gettin the 406 in my 69' camaro. If moneys not an issue its easier to go faster with bigger cubes obviously, or rather, it can have the same streetability, but with bigger power. Id say 406.

rtk434

iTrader: (1)

I never said I had tons of experience. I'm only 28. I have been doing this though for awhile and have built or worked on many small blocks. Both stock block 400's I have been involved with ended up with cracks on the deck sufacee between holes. I have ran several stock block,cast crank,stock rod 355's in the high 9's and low 10's with no issues. Not saying a 400 block can't hold up or be used though. I just feel the availability of a cheap, clean 350 core outweighs the couple extra inches. If he already had a 400 block it would be differant. My car currently has a nitrous small block that runs 8.70's in full street trim. Not the fastest in the world but by no means entry level. I've been through many many combos to get to this point. The car was bought in 96 as a stock 6 cyl. and 90% of the work was done by me at home in a 2 car garage. I'm no expert and was just stating my opinion. All things being equal I have not seen a 406 make that much more power than a 383. I guess what power level he is looking for and what his plans are make a differance as well.

Chevy406

iTrader: (12)

Well said RTK. If I had taken the time to look at your accomplishments (8 second club), I would have certainly kept my mouth shut. I would not want to run up against your car on the street. Forgive me for spouting off.

sick240

i would run him on the street, with fingers crossed he blows the tires off.

thanks for all yall input. my goals are pretty simple, wanting to step up the motor and keep it on pump gas and be able to drive the car where and when ever i want.

right now its just a 96 vortec motor with a gm hotcam some spray. the car has been 6.14 @112 in the 1/8 on the 250 shot, which was driven to the track.

i have heard people saying to do both with both 383/400 to 406 but was looking for some more input.

Ryan02SS

iTrader: (3)

Get as many cubes as your dollar will support. The 406 route will be more $$ over the 383. I just went thru this a few months ago and built a 385ci. A good 2 bolt 509 400 block that has been magnafluxed to ensure no cracks or core shift is at minimum $450-500. I found that hard to justify when I had 3 010 350 blocks to choose from.

Reliability is a washup. The 383 has a better track record but there are far more of them out there. Built right, both should prove very reliable.

As to performance the 406 will always outpower the 383 apples to apples. It has 23 more ci,a much larger 4.155" bore vs 4.030" which aids in unshrouding the valves and allowing for better flow and more power. Built with longer 5.7-6" rods they are much more rev friendly vs the 383 due to their bore/stroke ratio and rod ratio.

Either way you go should provide a decent power increase with that light car.

sick240, that's moving! Congrats.

ls1adamls1

iTrader: (9)

i'd go with the 383 set up personally. i have heard bad things about the 400 blocks over heating and cracking. just my .02.
i like the good ol 454 myself

moge11

What did this Z run on motor in the 1/8?

sick240

the fastest on motor has been a 7.20 and then 6.30 on the 150 shot you can see most of my passes on the link below, easy i know i need alot of body work.

sick240

thanks, its a fun little car. and i owe it all to my friend for all their time and help. just need to work on them to help with the cost. lol

ZONES89RS

iTrader: (25)

What trans you got in there and rear gear? @ gears in the 1/8th is not allot so i assume you dont have a huge rear gear in there.

67SS&99SS

iTrader: (7)

400 hands down. If you get a good 2 bolt main block, your gold. There are deals out there if you look. I was in a hurry to get a block so I paid $480 for mine, but it had been magnafluxed, vatted, and had never been bored. About 4 months later, I guy my dad works with had one up for sale for $150. I bought it too It was also a block that had never been bored out. Eagle is making 4340 forged steel internal balance cranks for them now, so that is what I bought for mine. Whenever you see any good 400 blocks for a decent price you better buy them up. The supply is dwindling down pretty fast.

sick240

it now has a powerglide with an 8.8 with 3.55s and held in place with a ladder bar setup.

Shawn @ VA Speed

iTrader: (3)

While i am a big fan of 400s myself,i would go with a 383,unless you have had a bunch of experience building and tuning 400s the 383 is the way to go,400s arent as forgiving as the 383,but they are far from the way people portray them-i went 8.20's on stock block 400 in a 3300lb car spraying the guts out of it-same block for 3 years