Hi all got a 2.5 sti block and was going to run that with my sti version 5 heads . What put me off was the matching of head to block and compression ratios etc . Now thinking more along the route of using the crank and rods from the 2.5 in my 2.0 block . My goal is 400BHP so the 2.5 sti crank and rods should be good for that . My question is what pistons will i need ? Also i assume the same thickness headgasket as currently used will suffice ?

v5 heads work very well with 2.5 block. For the cost i'd closed deck convert the block and put a decent set of rods in it or you will regret not doing them later.

I would ring one of the engine builders like Andy Williams , or engine tuner etc an get some advice as they know exactly wats required to suit your build . costs nothing for advice from the professionals

Wouldn't you need custom pistons to get the right height with 2.5 rods? In essence you're trying to build a 2.1 stroker engine hence best buying the correct parts off the shelf

Just need to pick the right ones, off the shelf mahle power pack will do the job

excellent, good way to get a cost effective strong engine for 400bhp

when you go looking at how many different ones are available it will blow your mind, Mahle catalog is huge hahaha

I still have the 2.0 rods as well but the 2.5 sti rods seem to get good reviews .

Cheers for suggestions but I already have the 2.5 crank and sti rods all I want is a definite type of forged pistons that will fit .

Mahle do a very good stroker piston in 4032 and 2618 grade with a compression height of 30.30mm to suit the standard length rods.

Mick

Cheers Mick do you mean 2.5 rods or 2.0 rods ? Any idea on part numbers ?

the 2.5 and 2.0 turbo rods are the same length @ 130.48mm centre to center.
Bolt type rods are stronger than the earlier nut type rods.
The 4032 grade mahle stroker pistons are SUB193642/16 for 92.50mm
The higher grade 2618 for extreme applications are SUB193642P16 for 92.50mm

Mick you are a great help many thanks