Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   454 rebuild with blower... Pistons and clearances. (https://www.offshoreonly.com/forums/general-q/321923-454-rebuild-blower-pistons-clearances.html)

airjunky 01-11-2015 11:38 PM

As soon a i find a 3.25 pulley mine is going together . With port fuel injection . Have a old 4 hole nos sprayer that i was thinking about fabbing up a alcolol inj sys above the throttle body like we had on a old datsun drag car running 25lbs boost not sure how the rotor lobes would like that though

mike tkach 01-11-2015 11:40 PM

i just finished a build very similar to what you are doing,it is scheduled for the dyno wednsday.it is 1 of 2 for another oso member.it is standard bore 454,8.5 to 1 compression ratio,afr 305 heads and a bob madera cam.it has wet exhaust so the cam is pretty conservative and it has to run on 89 oct fuel.it has a 177 blower that makes around 4 lbs boost.i am looking for 625 to 650 hp but more important to the owner is reliability.add in,it has scat h beam rods with arp 2000 bolts because they did not cost much more than rebuilding the stock gm rods with new bolts and they are a way better rod.also has morell hyd roller lifters.imo this engine should go 250 to 300 hrs before it needs the isky valve springs replaced and hundreds of hours before needing a refresh.i will let you know how it does on the dyno if you are interested.edit in,im no expert but i did stay at a holiday in express last week.

airjunky 01-11-2015 11:52 PM

With the gas prices down so much ill bet everybody now wishes spec for
93 octane . Who knows how long these prices will stay though.is this going to be run on dyno with wet exhaust ?

mike tkach 01-11-2015 11:57 PM


Originally Posted by billy boats (Post 4247757)
My old combo which ran GREAT!!!!! For 3 years before I sold it:
Gen. 6 454 .030 trw 2399 Pistons 8.8 compression
Bullet hyd roller .640 lift
Merlin iron heads 120 cc chamber 345 intake runner, 2.30 intake valve
Blower shop 250 No intercooler
Single dominator 1050
Thunder bolt 4 with V6 box
700 hp , 5800 rpm 5 lbs boost

7.5-8 compression with small blower will be a waste of time. Think of what that engine would make for HP if you remove the blower , 400 tops
In theory if you add 14.7 lbs of boost you double the HP, so at 7lbs you add 50% more. That makes the engine 600 HP , now take the parisitic drag of blower and heat caused by spinning that little blower SO fast to try and make 7 lbs. that's another 50-75 HP loss. So you left with 525-550 hp. Besides the HP numbers the engine will not be efficient at all.
The engine your looking for has been built for the last 25 years by every engine builder there is. Learn from other people's mistakes and successes.

billy,very well said and imo that was good reliable power.just think what that small engine would have made with the addition of some afr 305s.

mike tkach 01-12-2015 12:02 AM


Originally Posted by airjunky (Post 4248053)
With the gas prices down so much ill bet everybody now wishes spec for
93 octane . Who knows how long these prices will stay though.is this going to be run on dyno with wet exhaust ?

no,it will have the dyno headers with egt,s and a/f ratio hookups.the engine is speced for 89 oct because that is all he can get at his marina.

mike tkach 01-12-2015 12:13 AM


Originally Posted by ezstriper (Post 4247624)
the Merc 525SC only had about 7-1 and they ran well...8-1 will be fine with the blower

the 525 sc actually had a static ratio of 7.5 to 1.with the junk flat tappet cam and gm iron heads im suprised it made 525 at the flywheel.

TomZ 01-12-2015 08:16 AM


Originally Posted by airjunky (Post 4248049)
Lots of good points so far , prob should settle on your pistons and rings before you sweat the cylinder finish any more .prob wouldnt wouldnt theorize psi numbers too too much either .
a clean easy 5 psi through a efficient combo is as good as or better than 8 psi through a smog motor with a cam where the 3 psi extra is just bottlenecked boost and extra inlet temps really .
start looking for some extra pulleys now if you have the splined blower snout

Agreed.

I have a couple of pulleys now. I'm picking up additional pulleys as I see them come available.

TomZ 01-12-2015 08:21 AM


Originally Posted by mike tkach (Post 4248051)
i just finished a build very similar to what you are doing,it is scheduled for the dyno wednsday.it is 1 of 2 for another oso member.it is standard bore 454,8.5 to 1 compression ratio,afr 305 heads and a bob madera cam.it has wet exhaust so the cam is pretty conservative and it has to run on 89 oct fuel.it has a 177 blower that makes around 4 lbs boost.i am looking for 625 to 650 hp but more important to the owner is reliability.add in,it has scat h beam rods with arp 2000 bolts because they did not cost much more than rebuilding the stock gm rods with new bolts and they are a way better rod.also has morell hyd roller lifters.imo this engine should go 250 to 300 hrs before it needs the isky valve springs replaced and hundreds of hours before needing a refresh.i will let you know how it does on the dyno if you are interested.edit in,im no expert but i did stay at a holiday in express last week.

This sounds like a great combo and similar to what I'm after. Looking forward to seeing the dyno numbers!

mike tkach 01-13-2015 05:02 PM

tom,the dyno sesion got bumped to today,just got back.it made 690 at 6000 rpm with a safe tune.i was expecting 625 to 650 so i and the owner am pleased with the results.

Black Baja 01-13-2015 05:25 PM


Originally Posted by mike tkach (Post 4249055)
tom,the dyno sesion got bumped to today,just got back.it made 690 at 6000 rpm with a safe tune.i was expecting 625 to 650 so i and the owner am pleased with the results.

Just curious what kind of torque did it make?


All times are GMT -5. The time now is 11:21 AM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.