500 stroker question

Posted By: mopfried

500 stroker question - 04/08/11 02:56 AM

I am thinking of a 500 stroker for my 69 dart based on a 440 +.030 overbore and an Indy 500 stroker kit. The compression ratio worries me. what kind of static compression can I run on pump gas... What cam would be streetable on a 500" motor? I am not looking for max hp but something impressive.

Posted By: fourgearsavoy

Re: 500 stroker question - 04/08/11 03:22 AM

It all depends on your heads and piston type

You should read AndyF's book on HP bigblocks there is some good info in there about piston and chamber design

Gus

Attached picture 6574138-burnoutpicturegus.JPG

Posted By: challengermike

Re: 500 stroker question - 04/08/11 04:00 AM

mines 9.8 to 1 with 906 heads and no problems.That with KB pistons and a cat stroker crank and rods.

Posted By: 451Mopar

Re: 500 stroker question - 04/08/11 07:19 AM

With 500 cubes you don't need alot of compression for the street, but the engine will want alot of airflow and cam.
I have gathered up almost all the parts I need to build my 440 into a 505" stroker.
I'm using the 440 source 4.25" stroker kit with 7.1" rods and 17cc dished pistons (0.030" over), with the older 84cc Stealth heads. That should give me 9.93:1 compression. I haven't ordered a cam yet, but I'm leaning towards the Comp hydraulic Roller cam XR286HR10. The cam is 236/242 duration@0.050, 0.544"/0.541" valve lift with 1.5:1 rocker arms, 110 lsa, 106 cl. I'm using 1.7:1 rockers, so the valve lift should be 0.617"/0.613".

Posted By: 1hirschdalemopar

Re: 500 stroker question - 04/09/11 04:09 PM

I am in the process of gathering parts for my stroker 500 right now (same set up as 451mopar)and andy's book is a must read.I to have not chose a cam yet , (hard to decied).Anyway I am shooting for 10.3 to 1 with a large enough cam to bring the dynamic compression down below 8.5 to 1 so it will be pump gas friendly.
After reading andy's book there are a lot of other factors involved than just static compression ratio , (quench , aluminum , iron heads , combustion chamber design , pistons , etc.)
But I think dynamic compression ratio is more important than the static ratio when it comes to running pump gas.

Posted By: ahy

Re: 500 stroker question - 04/09/11 05:09 PM

As a general guide, 9.5 CR for iron heads and 10.3-10.5 for aluminum on pump gas. If you build the engine for quench - meaning clearance between the flat part of the piston and flat part of the head at TDC is .040" - detonation resistance will improve and you can run higher compression and/or more timing and/or lower octane fuel.

At 500" you will almost certainly need a dish piston to get CR where it needs to be for pump gas. A "D dish" piston keeps has a flat area to create quench with the head.

A bigger cam can take more compression so cam choice matters. After you have choosen a cam, you may get more specific advice. Gearing, convertor and application also influence CR choice. Sustained hard running builds up heat and can cuase detonation so CR has to be a bit lower.

I choose 10.2 with my 496/Ed head quench engine to keep a little detonation margin for sustained hard running in a road race application.

Posted By: mopfried

Re: 500 stroker question - 04/09/11 06:39 PM

The Indy kit I am considering states 12.5 with 75 CC head. I can get sidhed pistons.. I am considering buying this kit used at a great price so new pistons may not be out of the question. The cam that is witht he kit is the largest befor a roller cam.. Dont know the exact specs yet. I want this pump gas and steetable.I have drove over cammed motors on the street and its no fun.

Posted By: JohnRR

Re: 500 stroker question - 04/09/11 07:56 PM

Quote:

The Indy kit I am considering states 12.5 with 75 CC head. I can get dished pistons.. I am considering buying this kit used at a great price so new pistons may not be out of the question. The cam that is with the kit is the largest before a roller cam.. Don't know the exact specs yet. I want this pump gas and steetable.I have drove over cammed motors on the street and its no fun.

It would have to be a smoking deal to have to buy another set of pistons and a cam , though you can sell those extra items .

Posted By: Twostick

Re: 500 stroker question - 04/09/11 08:58 PM

My 493 440Source kit came in at 8.97:1 with a 30something CC dish Ross piston and OOTB Eddies. Gotta like 500hp on regular gas.

Kevin

Posted By: 383man

Re: 500 stroker question - 04/10/11 05:00 AM

I am building a 493 for my 63 and I am using Indy EZ heads. I had to get the dished piston to get my comp down to 10.6. I am using an agressive cam that Dwayne Porter speced for me. It should run fine on 92 or 93 pump. The cam has alot to do with it also as it can have a big affect on cyl pressure which they say keep it below 190 for pump. Ron

Posted By: 383man

Re: 500 stroker question - 04/10/11 05:02 AM

Here is the pistons I am using. Ron

Posted By: Kern Dog

Re: 500 stroker question - 04/10/11 08:57 AM

Quote:

Here is the pistons I am using. Ron

These look almost too nice to hide INSIDE the motor.

Posted By: mopfried

Re: 500 stroker question - 04/10/11 02:08 PM

Quote:

Quote:

The Indy kit I am considering states 12.5 with 75 CC head. I can get dished pistons.. I am considering buying this kit used at a great price so new pistons may not be out of the question. The cam that is with the kit is the largest before a roller cam.. Don't know the exact specs yet. I want this pump gas and steetable.I have drove over cammed motors on the street and its no fun.

It would have to be a smoking deal to have to buy another set of pistons and a cam , though you can sell those extra items .

It is a smoking deal...fresh block .030 over, stroker kit, teo sets of heads two trannys almost everything to assemble for not much more than the stroker kit...

Posted By: Dodgem

Re: 500 stroker question - 04/10/11 02:39 PM

With a big cam and aluminum heads you can run pretty high compression on 93.
I ran 12 to 1 last year on 94 think I could get by on 91.

Posted By: 451Mopar

Re: 500 stroker question - 04/10/11 08:45 PM

Here is my 17cc dished piston (and pin) for 7.1" rod, 4.25" stroker:

Attached picture 6578428-505piston.jpg