Advice for 355

[drew852]

hey guys just want some opinions on a 355 im building, ive done a fair bit of block grinding and polishing, its pretty much got no cast lines anywhere and is smooth and shiny throughout the gallerys.
its a 304 block out of a vs,
h286
1350 cfm harrop 4 barrel
single plaine manifold
ls1 injectors
scat 355 crank
hypertec flat tops
20thou over
decent fuel setup, cant remember but would never be possible to restrict it
roller rockers 1.65
manual
3.7 diff gears solid diff
comp would be real close to 10:1
heads are standard but ive polished the **** out of exhaust side and the bowls
single 3inch with pacemakers maybe upgrade to dual 3
what do you guys reckon a good power figure would be? im hoping to get close to 400hp at the wheels, if you reckon im way off please do speak up, I would love everyones opinions cheers

 

[Deuce]

hey guys just want some opinions on a 355 im building, ive done a fair bit of block grinding and polishing, its pretty much got no cast lines anywhere and is smooth and shiny throughout the gallerys.
its a 304 block out of a vs,
h286
1350 cfm harrop 4 barrel
single plaine manifold
ls1 injectors
scat 355 crank
hypertec flat tops
20thou over
decent fuel setup, cant remember but would never be possible to restrict it
roller rockers 1.65
manual
3.7 diff gears solid diff
comp would be real close to 10:1
heads are standard but ive polished the **** out of exhaust side and the bowls
single 3inch with pacemakers maybe upgrade to dual 3
what do you guys reckon a good power figure would be? im hoping to get close to 400hp at the wheels, if you reckon im way off please do speak up, I would love everyones opinions cheers

Sounds like a good combo. Have you cc'd the heads so you can calculate comp ratio (rather than guessing). What rpm will you be spinning to?
You will be in the 300s rwhp range. Not sure if it will crack over 400 though.

 

[Immortality]

A well built combo with that cam might get close to 400 fwhp but not 400rwhp.

I would be shooting for about 10.5:1 CR.

I think a full twin 3" system would be to big unless your only worried about peak power.

 

[billyj]

i think you will find with flat tops your comp would be well up into the 11's you want about a 12ish cc dish to be in the 10's. also as i found out recently the hypertec pistons to suit a 355 crank with holden rods are nla, its either forgies of fit 5.7" rods and use 383 chev pistons

 

[Vs hsv manta]

I doubt a combo like this will see anywhere near 400rwhp

For that power up you need a full on built 355 with full race port heads, a solid roller cam in the 250s range with nearly 0.600 lift and high 11 comp or nearly Into the 12

Nearly all the power in a holden is in heads and yours are standard beside a smooth out

Won't see past 300rwhp N/A and stock heads no matter what you do

You will only make as much hp as your weakest link and at the moment that's your heads as that's pretty much the first part to upgrade on a holden engine

 

[drew852]

thanks heaps guys I appreciate the feedback, ive decided to change over to the h304 and new valve spring, im also gonna do more work on the heads to get them flowing a bit more, I thought I read someone on here getting 400+rwhp with standard heads? maybe wrong. I really hate piecing a combo together and sending money to the dump as I call it, but I guess you gotta learn to get hp, the block is off to get some trimming done next week so ill try get some pics up and keep yas posted. also what would yas recommend on the computer side of things? im new to holden computers but I no my rig has a chiptorque in it, can I get it retuned? cheers boys

 

[drew852]

cheers, the guys reckon they will sort out pistons with the kit, if no more hypertec left they get whatever equivalent

 

[drew852]

have not ccd the heads until after I get the valve job done, rpm will be up at 6500

 

[Vs hsv manta]

Honestly mate just send your motor to Pavtek and if you seriously want 400rwhp then get there gold pro motor

If you want something a bit more user friendly get the silver stroker

 

[mr j-man]

in all honesty ditch the hydraulic cam!!...
And you gotta do something with your heads as any cam with a bit of duration and lift will just be a turd!!

Flat tops and a 0 deck height will see you around 11.0:1 comp depending head CC.

And honestly if your going to send a motor all the way to pavtek you may as well save half the freight costs and send it to Horsepower Engineering or Zoks Race Carbs

HorsePower Engineering
https://www.facebook.com/HorsepowerEngineeringAustralia


https://www.facebook.com/pages/Zok-Race-Carbs/205182829505334