Correct 383 HP pistons?

[oestermarken]

Are these pistons a good choice for a almost stock 383 HP rebuild?

Speed-Pro Forged Pistons L2315NF30
http://www.summitracing.com/int/parts/slp-l2315nf30/overview/

The compression height seams a little lower than the original pistons, but I can't find any closer to original height.

Thanks, Brian

[John_Kunkel]

If the block is the correct 9.98" deck height those pistons would be about .012" down in the hole. The '68-'69 HP pistons had positive deck height but other years were down in the hole; .012" down isn't bad depending on what heads you're using.

[oestermarken]

I'm using my 906 heads.
Do you know if there are any alternative pistons out there?

Brian

[Mebsuta]

Pistons of the original compression height are not available any more.  I think the Speed Pro you have linked is the closest.  

There's the KB-400, which may give higher compression, but it's not a flat top like the original.  I have never heard or read anything from anyone who has used the KB-400.  

[BSB67]

The 68/69 pistons are 1.932" IIRC, and from the factory were not above the deck.  The blueprint spec is like 0.020" above the deck.  The piston you are looking at will probably be about 0.020" below the deck in an uncut block.

That piston, the right head gasket, and a set of 915 heads is a nice starting point for a high performance street motor.  You'll get quench and a decent compression ratio. 

The kb 400 is an option for a bit more compression than you will get with the 2315s with the 906s, but no quench.

[oestermarken]

Thank you for the replies guys  

My original pistons was very close to zero, I should maybe have measured a little better, but at the time I thought I was going to reuse the old pistons.

I think I like the flat top style pistons best, in case I'm going to switch to some closed chamber heads in the future.

Do you think the best way to go is to get the 2315s and mill the block 0.015 to compensate for the lower Compression Distance?


Brian

[70-500-SE-EXPORT]

I have the kb-400 pistons and love them. They were the best ones I could find to replace the original 68 hp pistons without loosing compression. There's not much choices for non forged pistons for us with 383's unless you go custom. I thought the compression may be too high and I would have detonation issues but that was not the case. Haven't noticed any detonation.  I'm using the stock 906 heads that were resurfaced and the block was decked to square it up.  It runs very strong and has much more power than I expected. I'm using a roadrunner resto cam, holley 770 and firecore dist. I am very happy I did not buy the lower compression KB pistons that were recommended!

[oestermarken]

I have the kb-400 pistons and love them. They were the best ones I could find to replace the original 68 hp pistons without loosing compression. There's not much choices for non forged pistons for us with 383's unless you go custom. I thought the compression may be too high and I would have detonation issues but that was not the case. Haven't noticed any detonation.  I'm using the stock 906 heads that were resurfaced and the block was decked to square it up.  It runs very strong and has much more power than I expected. I'm using a roadrunner resto cam, holley 770 and firecore dist. I am very happy I did not buy the lower compression KB pistons that were recommended!

great info!  

I think your engine is very close to what I have in mind with mine.
Do you have more engine details, did you use the original connecting rods, was it  necessary to have your crank balanced?

Brian

[70-500-SE-EXPORT]

Glad to help. I used the factory rods and had them resized because they were mis aligned and had arp bolts installed. I did not have the rotating assy balanced because my machinist said it wasn't needed but I think I should have for peace of mind as the factory balance job probably isn't that great. I do not have any noticeable engine vibrations with the new pistons. I am also using the edelbrock performer rpm intake. I am vey happy I did not get a 440 this 383 surprised me and is much more powerful than I expected. I very happy with the power and fuel mileage. I doubt it would have run this good with the lower compression pistons that were recommended because I was using iron heads. Good luck with your build