I have a 355 short block im building up, but im worried the compression ratio is to low.

-Superram
-Forged h beams
-Forged dished blower pistons
8.5 compression with 64cc heads, not supercharging

I will be buying new aluminum heads and cam. Looking for 375-400 hp without my 150 shot.

 

why are you using piston that don't fit your application?

 

Yeah your going to have problems getting enough CR with those pistons. Use a thinner head gasket and mill the heads to get 54 cc and you should be around 9.5:1. Best thing to do: Get new pistons!

 

Just my .02 but i highy doubt your going to get 300HP at the crank with a mixed and matched motor like that.

If your not supercharging why did you go with such big dish blower piston?

 

For my twin turbo setup, that im not going to use. But i already built the motor for them.

 

Pull the pistons and try to get a few dollars for them on ebay. then grab some flattops or something to get the CR up to a reasonable level, Especially if you want to see those numbers.

 

Problem is that i balanced my rotating assembly, so i will be throwing $250 out the window. Then on top of that i will have to rebalance the new pistons with my crank.

So $500 when all said and done.

 

Its probably going to cost you the same ammount to get your heads milled down enough to get a descent CR. Then you might end up with piston-valve clearance issues.

Balancing is not 100% necessary unless you plan on keeping this engine in the 7k RPM range all day.

 

I was also thinking i could sell the rotating assembly to someone going with forced induction.

Pistons, crank, rods, flexplate, harmonic balancer

 

The key word here is "thinking" ....Nothing like good planning and thought to ensure the success of any venture.

Why did you give up on the supersharger?

 

It was twin turbos...

I will be looking into getting a low compression forged rotating assembly for my blown buildup but im not going to do anything till spring now. If you by chance still have it next summer i would be interested.

 

I am giving up on the twin turbos for many reasons.

-oil return lines are a pain
-no A/C ( im in Texas! )
-730 computer being a pain
-laptop broke
-turbo pipes from the intercoolers to the intake need to be redone
-by the time its done it will not be a very streetable car
-this is my everyday driver
-lots of fabrication still left

And of course i would still need to throw a ton more money at it to get it down the road.
-intake piping
-exhaust custom y pipe
-ceramic coating

Did i mention i live in TEXAS! No A/C sucks!

It is going to be hard to let them go though, their so pretty!
And i have thrown so much maoney at them.

 

Why not mount them at the back, behind the axle like they do at Squire Turbo Systems ????

A slick way of solving lots of the typical turbo install headaches. Don't really need a intercooler either.

 

Doing that still wouldnt solve most of my problems and it would cost me even more money.

 

Big chamber heads and a blower with high boost pulleys? There's a couple of 58cc heads with decent runner size out there otherwise.. Can't you safely run more nitrous with lower compression? It might mean "only" having 350hp, probably get away with spraying a lot more like a 250 shot or 300 with a progressive controller. I'm just throwing ideas out there for ya, most heads can be flat milled .020 without doing the intake to match. After that you get into angle milling, bolt holes might need shimmed and elongated, intake milled, could involve milling the head bolt holes individually, valvetrain may need special length pushrods. I dunno, none of it is that difficult just time consuming how well are you in with the guys at the machine shop?

 

Not really but i have alot of my own tools.

 

anyone interested in my rotating assembly

forged pistons TRW L2441F30
forged H beam rods Scat
scat crank
harmonic balancer
flexplate all balanced with weight info card

 

How much $$$???

 

you could have the shop that balanced your assembly match the new pistons to the old ones. this would cut down the cost . good luck