383 or 408?

[markcp]

Currently I have a 355 SBC in my 78 Monte. Due to some oil issues, I'm looking to go in another direction. My friend runs a speed shop and has offered two different solutions. Both options, would have me trading my 355 to him as is. I do not have specs in front of me at this time for either 383 or 408 build.

#1 383 with roller lifters, pretty much turn key
#2 408 with many of my parts off my 355. (heads, intake, carb, etc.) Hyd lifters Price $300 less than 383

The car is mainly a cruiser. Turbo 350 trans, stock rear end with 3.23 posi.

Any thoughts on selections? I'm not looking for other upgrades at this time, such as Ford 9". Want to get the power plant first.

Thank you,
Mark

 

[454muscle]

Spend the extra $300 and get the turn key 383. Any warrantee's with either of them?

 

[84dragcutlass]

^^^ i agree the extra money would probably be best goin toward the 383 more than the time bomb the other is sure to be. Especially for a cruiser

 

[84cutlass454]

there is no replacement for displacement the 400 sbc is a beast bbc cubis with less weight thats whats in this iroc 10 sec street car on 250 horse nos

 

[Qdub24]

For a cruiser I'd choose the 383. As for the 408 you speak of, is it built with a SBC 350 or 400 block? I've seen one in a magazine built with a 350 block that I wouldn't want to drive on the street.

http://www.chevyhiperformance.com/tech/ ... ombos.html

 

[JBreu]

Maybe I'm partial..................go with the 383.... I have the same version only mins is punched .060 ove, making it a 388 😀

 

[SafariWagon]

More discplacement the better. BUT you say 408, correct? Not 406? A 400 has siamesed cylinders. There is no coolant flowing between them to help cool the engine. 040 over is max IMO on a street 400. I would not go .060 on a 400 myself. They tend to run hot. For your combo a roller cam seems a bit overkill to me in the 383 as well. I would go .030 400 and a mild hydraulic cam. Remember to drill for coolant holes in the heads if you are using ones that were on a 350. All 400's should have this as well because of the already mentioned siamesed cylinders.

 

[dogsht]

As long as your speed shop owning friend will back the 408 and help you if there are any cooling issues. The 408.

 

[megaladon6]

agreed on not using an old overbored 400, just not a good idea on a cruiser. while there are plenty of ways to fix the cooling, if you ever need to do a rebuild or rering there may not be enough material to refinish the cylinders.
but no matter what you do, use a roller cam if at all possible. flat tappets need oil with ZDDP additive which is getting hard to find, and pretty much impossible in a synthetic oil. rollers have fewer frictional losses, have longer effective duration, and last longer. plus you don't have to replace lifters if you change cams. unfortunately they are more expensive (if it's not an original roller block) and require a specific distributor gear material, sorry i can't remember which one.

 

[86Cutlass383SR]

I'll toss in my 2 pennies worth.

MOST 400's can only be bored .030". If the block has nos core shift, they can be bored .060". But most 400's do have core shift and are hard to find moe's that don't. Sonic testing is the only way to check for sure. A 408 is on;y bored .040" over, a .060" overbore would be 412 or 413.

Listen to what megaladon6 said about the cooling, heads, and flat tappet cams.

My Comp Cams hyd roller has a cast iron gear pressed on allowing a stock cast iron distributor gear to be used. Some GM dist gears may be *melonized*, too. A lot of roller cams are ground on a steel billet core and these require a bronze or maybe a composite dist gear. The bronze gears wear quickly and require frequent replacement.

A good 383 will have all the torque you need in a street car. Just ask any 383 owner ...