Hot rod bench racing?

[Pullstart 62,840]

I’m on the hunt for a customer engine.  He wants 450 hp or so.  
 

Richard Holdener built a 383 and here are the details.

 

383 10:1 compression

432 hp 473 lb-ft

Comp cams XFI .570/.575 lift, 218/224 duration, 113LSA

64cc chamber heads 

Dual plane rpm air gap intake

770 street hp Holley 

1-3/4” headers

Electric water pump

 

 

My Uncle in Law has an engine for sale.  The photo details the build.  Any accurate way to guess the power output?  Obviously not the 450hp goal, but good bones to build on.  Maybe the pistons and co bastion chambers just won’t warrant 450 hp..

 

 

[ebinmaine 67,455]

Do you have the full specs on the cam and heads with part numbers?

 

[ri702bill 8,316]

Kevin: The only way to settle it is to dyno it - they can tweak the timing & carb to squeak out the max. You will either be surprised, or disappointed... but you will know what it can do....

[Pullstart 62,840]

1 hour ago, ebinmaine said:

Do you have the full specs on the cam and heads with part numbers?

 

no I don’t.  I guess their runners and whatnot matter a ton.

 

36 minutes ago, ri702bill said:

Kevin: The only way to settle it is to dyno it - they can tweak the timing & carb to squeak out the max. You will either be surprised, or disappointed... but you will know what it can do....

 

but it’s not mine 

[Pullstart 62,840]

@Greentored you still out there buddy?  Any thoughts on potential power output from the 355?  Would a cam swap warrant anything close to mid-400 hp?  He’s not worried about vacuum for brakes, has thought about going with an electric pump kit.

[lynnmor 7,305]

I built the 355 in my van using stock 1.94 heads, Qudrajet carb., high lift cam, 9.0 to 1 pistons and numerous upgraded parts.  It is not a big upgrade and my butt dyno says 225 HP.

[Greentored 3,201]

On 4/25/2022 at 8:35 AM, Pullstart said:

@Greentored you still out there buddy?  Any thoughts on potential power output from the 355?  Would a cam swap warrant anything close to mid-400 hp?  He’s not worried about vacuum for brakes, has thought about going with an electric pump kit.

I am!! haha!  So we're looking at a guesstimate on the output of that 355? Would need to know exactly what model the World heads are as well as cam specs. If I was to guess, a cam with .480ish lift is on the mild side, as well as 9:1. A general aftermarket head like a world products is a major gain over oem stuff.  Id say that engine is good for 350hp/maybe 400tq and probably rock solid dependable.

I used to do a 355 drop in kit for the old TBI 350s- it was 9.7:1, small .450lift RV cam, dual plane intake and stock GM Vortec heads- they would make 325hp/400tq on the dyno and go over 100K miles, and get 20mpg.. This 355 is very similar as the vortec heads are awesome and rival the aftermarket stuff, and the cam is just a bit larger.

Edited April 30, 2022 by Greentored