HP and 1/4 times

[Guest chevsun]

I am looking for help from the people with software. I am building a

377 and want to know what to expect as far as hp and 1/4 mile times. The info is, car at 2800lbs caged, wet, with me in it, engine is: 4340 steel cat crank, windage tray, and scraper, 6" h-beam rods, 2bolt 400/w splayed milodon caps, 10:1 srp forged pistons,plasma moly rings, edelbrock RPM heads intake and 750 carb, I havent purchased a cam yet but If someone could plug in something like a hyd. roller/w .520 lift and 110 lsa or make a sugestion please. petronics ign., elect fuel pump and fan. Hooker block hugger headers 2 1/2 dual/w crossover and hooker aerochamber mufflers. This is hooked to a t-56/w Mcleod flywheel and street twin disc clutch. ther is no slip in this unit with the 350 I am running now and it hooks "OK" I am running a 3;90 rear and 14" drag radials could someone tell me what I might expect for HP and times. I have everything but the cam so I will be open to suggestions. I also have yet to put it together as the block is in the shop right now so I am open to any improvements or things to look for. thanks steve

[Kevin Shasteen]

What RPM are you wanting your engine to come in to [peak power] at(?); 5500 or 6500rpms? To know your RPM's at the 1/4 I need the full tire measurement 190/60/14's ect, ect.

 

A 2800lbs car w/400 RWHP will click the 1/4 mile @ ET = 11.14; while a 2800lbs car w/350 RWHP will click the 1/4 at ET = 11.65 while 300 RWHP will gain you a 1/4 mile ET = 12.26

 

If it's 5500rpm-then you'll need a cylinder head whose Minimum Port Intake Volume equals 1.72 sq.inches. If your peak power is 6500rpms then you'll need a Minimum Port Intake Volume of 2.0 sq.inches. The Port I'm referring to is the intake port on the cylinder head/more specifically-right where the air enters the cylinder head. (Just tell your engine builder what you need-or the tech line/they should know what you're talking about).

 

What static compression ratio are you wanting?

 

I used Brodix -8 heads which flow at 220cc @ .500 lift at 25*Degrees Pressure Drop. Using those figures w/a Hydraulic roller they should be good upto 475 HP: then your power will begin dropping: RPM's will still continue-but power will begine dropping. This assumes the only restrictions are the cylinder heads & not the intake/exhaust systems!

 

As for compression ratio (are your piston's flat top's? slight pop-up's w/slight valve relief's?

 

Lets say you chose a cylinder head w/67cc; add that to the quench of .060"-converting this to cc's = 12.54cc & add this figure to your Cyl.Head's combustion chamber of 67cc = 79.54 (or 80cc final combustion chamber).

 

Using the above final combustion chamber-you should obtain 10.5:1 Comp.Ratio (pushing the limits of pump gas). Now if you chose a 76cc cylinder head w/12.54cc Quench then you'ld get a 9.5:1 Comp.Ratio.

 

For the 10.5:1 Comp.Ratio you'ld need a camshaft whose Intake Valve closed 54*Degrees ABDC. Whereas the the 9.5:1 Comp.Ratio would need an Intake Valve closing of 47*Degrees ABDC. BTW: the 47* or 54* requirements are the Seat to Seat (or opening to closing) figures-usually taken from the .006" opening on the cam bank to the .006" closing of the same cam bank figures.

 

This is mostly speculative as I dont know the exacts of your piston top's. But I did configure my answers from the use of a 377 w/6"rods. So you should be close to your objective-dependent upon if you plan a race fuel engine only or a pump gas engine(?).

 

BTW-no software...just a calculator/some things must be done the "Ole Fashion Way!" (haha)

 

Kevin,

(Yea,Still an Inliner)

 

[ June 17, 2001: Message edited by: Kevin Shasteen ]

[Guest chevsun]

Hey Kevin you blew me away with the numbers. Thanks. I have a question about quench. I was reading somewhere that total quench should be no less than .039 no more than .045 for reasons of detonation and overheating. I don't have the knowledge to dispute any of these # but sure would like to know for sure before I do the final assy. I have 2 posts from chevytalk.com from a supposed GM powertrain engineer reguarding quench that I would like to e-mail you to get your thoughts on if you don't mind. My e-mailis speaker@together.net send me your e-mail and i will send you these posts .

To give you a little more info on what I have. The heads are edelbrock #6089 64cc heads with 170cc intake runners. The pistons are flat tops and are supposed to make 10:0 I hope to be able to get my power at 6500rpm with this setup. The tires are 205-60-14 BFG drag radials. thanks for your interest. Steve

[Kevin Shasteen]

Hey Steve,

 

Thanks for the vote of confidence. I've read where the intake ports on those Edelbrock cyl.heads are suppose to flow 216cc at .500 valve lift; with your choice of hyd.roller-should be good for 465hp..providing again-your only restrictions are the cyl.heads & not the intake nor exhaust system.

 

Those cylinder heads should be great for the street; the ports are not too large where airflow will be too minimized at low rpm's (all dependent on your camshaft choice-hyd.roller should be more user friendly) nor are they too small that high rpm will be diminished. The max RPM depends on the [minimum port volume]; unfortunately this is not a number that mfg's lists. Its moreso something the individual has to measure. Simply measure [Height x Width] to obtain [sqaure inches]: be sure you measure the port exactly adjacent to where the pushrods go thru.

 

Once you've got that number (in square inches) use this formula where Limited Port Volume = LPV:

 

Max Rpm = LPV x 184,136/Bore^2 x Stroke

 

BTW: this formula is only good for a Hydraulic Roller.

 

Your tires are 23.68"Tires in Diameter & should yield you 117.46mph @ 6500rpm's and 108.43mph @ 6000rpm's. It all depends on the actual torque/hp your engine puts out and of course that was at a 1:1 trans gear ratio with you being in 4th gear.

 

I wish I could build a 377; I like the idea of a "Rev-Happy" SBC V8; especially in a light car like the Z.

 

About Quench-the best article I've read was here recently. It was on "Speed-o-motive's" site under their "Engine Building Tip's": Lone posted an answer to someone here in another forum & gave the site as one to look around...so I did. I really like their "Engine Building Tips"...it was very informative. Do a search on the web for "Speedomotive"-you'll go right to it.

 

They did say that if you're using hipo parts w/steel rods & steel crank you can deck your block to .010 or a "0" block deck as long as your head crushed head gasket thickness remained .035" which was the minimum thickness you could get away with providing you kept your rpm's under 6500rpm.

 

You can email me your article by clikcing on the "Letter" icon at the top of one of my posts as I'ld be happy to read it...always looking forward to furthering my knowledge at someone else's hard earned experiece.

 

Kevin,

(Yea,Still an Inliner)

 

[ June 17, 2001: Message edited by: Kevin Shasteen ]