383 questions...

[Fabrimacator21]

I'm planning on pulling my 355 and putting new a new set of heads and a different cam but now I'm wondering if I should just go ahead and throw a 400 crank in there while I'm at it. I know the block needs to be clearenced but would I be able to keep my old rods and flat top pistons? Also how would the extra stroke affect compression?

 

[bot0611]

Id stick with the 355 unless thoose rods are 5.7 lenght

 

[Fabrimacator21]

Can you elaborate? Is it not possible to use 6.0" or is it just less desirable?


I'm wondering about the compression also. Would I have use a thicker head gasket?

 

[toomany]

383's need special pistons. Meaning that you can't drop a 400 style crank into your 350 and be good to go. The skirt will be hitting the crank throws. Swapping to a 6" rod with your current pistons won't work either, they will come out of the hole at TDC. The compression height of the pistons must work with your rod/stroke other wise you will have some weird compression ratio, or valves hitting the pistons.

If you need a new crank, or pistons. Then I'd spend the extra to build the 383.

The rod length will affect the rod ratio...I don't know what the ideal is. Rod ratio equals the length of the rod divided by the length of the stroke. I'd assume the ideal is around 1.6:1, but I'm no expert.

Stroke (inches)-------Rod Length (inches)-------Rod Ratio

3.48-----------------5.7----------------1.64:1
3.48-----------------6.0----------------1.72:1
3.75-----------------5.565--------------1.48:1
3.75-----------------5.7----------------1.52:1
3.75-----------------6.0----------------1.60:1

 

[Fabrimacator21]

Ok... thats what I wanted to know. Thank you.

I guess she'll stay a 355.