Can i measuse across the rails and determine how much would need to be clearanced?

I want the max stroke in my 402 probly .040-.060.

4.25" stroke? or is 4" the max.Would i need a tall deck to get the 4.25" in there.

Forgot to add its a 72 402 which i was told is similar in design to the 454.So if a 454 will take a 4.25 stroke i guess the 402 will too.

My '74/'75, 454 P/U block took my 4.25" arm like it growed in there! I bet a 4.375" arm would even fit!!

You know, why go longer when with either a stock 502, Bow-tie or aftermarket block with a 4.53" bore you can get up to 564 fairly easy!!! pdq67

I want to use a small bore.Im not looking for big inches overall ,im looking for long stroke.

What would determine max RPM? I've seen some 454-502's built and they redlined about 5,000.What determines that redline or max rpm.I know its the mass of the parts and the long stroke also the cam but which really holds it back more.

Say if i wanted to build a 4.166 bore 4.25" stroke BB, would it only rev to 4,000? then just would not rev any higher or would that 4,000 just be the max safe rpm for the weight of the parts.

I'm guessing its just the weight of the parts not the long stroke since the top fuel guys run longer strokes than 4.25.

I still want it to rev to maybe 6K.With the right cam and light weight parts would it go to 6K.

It's not this stuff you are in to but rather matching everything together.

Just check out the spec's on that little high winding Honda 2000S or whatever it is called that is factory redlined at 8200 or so rpm!!

I hope I have the right name??? pdq67

I don't get it......

If its a 396 block you might need to take a die grinder to some corners of it I hear ( same as 427 block with a 4" crank). Before you get all into buying a Callies Dragonslayer 4.25" make sure you can get pistons for your combo.

Flatlanderracing.com seems to specialize in strokers.

<BLOCKQUOTE>quote:</font><HR>If its a 396 block you might need to take a die grinder to some corners <HR></BLOCKQUOTE>

It's a 72 402 same block dimensions as a 454 i think.Thats what i was told.

I think for the later blocks you might be right. Should drop right in then ! http://www.chevelles.com/forum/smile.gif

Supersport,

What I'm trying to say is that after checking out the spec's on the little 8,200 rpm redline ricer engine, I see that all you really need is to make sure the rod/stroke ratio is OK and that if you have enough valve area to feed the engine, then even an undersquare engine, (i.e., small bore, long stroke), can run with the best of them!! Witness the little before mentioned ricer engine!!!

And this has nothing to do with what you really were asking about but none the less applicable!! pdq67

Ok,i get it now,a piston speed of 3,500 fpm (Feet Per Minute)is considered max for a typical stock 4 stroke engine and around 4000 fpm for a mild modified engine(Crank,Rods Ect).

So my 6K goal would be at 4233FPM.

I think i could make it to 6K.I was thinking the longer the stroke the less it would actually be alowed to turn but its really just mass and piston speed the determined that.

Light rods and pistons and i should be fine for 6K.

That 2.0ltr has a piston speed of 4,575fpm @9,000RPM.

Why would you want to use a small bore with a long stroke? I don't get it.

The small bore will really hinder air flow through the cylinder heads (valves will really be shrouded compared to a 4.250"+ bore block.

Also, with the added cubes, it's important to be able to feed those cubes the needed air and the small bore again, limits the needed air flow.

I'd rather have a larger bore with a smaller stroke, then a huge stroke and a small bore.

I wouldn't be surprised if the 396/402 blocks had more material in the bottom of the crank case since they were designed for the shorter 3.760 stroke crank from the factory. It might require some serious grinding to clear a longer stroke crank...just guessing there though.

------------------
Malibu Motorsports (http://www.malibumotorsports.cjb.net)
414 ci bbc, 3500 lbs
10.66 @ 125 1/4 mile
6.74 @ 101 1/8 mile
1.48 60' on 9" tire

<BLOCKQUOTE>quote:</font><HR>it's important to be able to feed those cubes the needed air and the small bore again, limits the needed air flow.
<HR></BLOCKQUOTE>

I would think the heads and valves would do that,not the bore.The smaller bore has a beter flame travel and burn than the big bores.

Smaller valves also mean less weight,but i think 454's 502's have the same valves as my heads would have 2.19 1.88.502's use 2.25 1.88's.So dont think that would be a problem.

Most high reving engines have fuel and airflow problems.

You got it but look into what it takes to get the rod/stroke ratio at or above 1.7 to 1 in a long stroke big block like the big 455 Buick has..

Guy's he's on track about the smaller bore engines being more eff. combustors but generally we see that smaller bores do limit breathing more then the efficient combustion makes up for lost breathing ability!

And, as strange as this sounds, a head with the valves perfectly perpendicular to the piston, along with a centrally located sparkplug, if the ports are at very high angles and the heads are completely open with zero quench but rather just with piston deck height quench are about the best there is until you get to the four-leaf clover, LT-5 head design!!!

As always, jmho. pdq67

Wouldn't my r/s ratio be the same as a 540 or something like that,6.385" rods.540's work.

Rod/Stroke ratio =Rod Length ÷ Stroke
Degree =.5/rod ratio

540 =rod angle 19.43degrees
Ratio= 1.50

Hows this,a 454's r/s ratio is 1.54,not much better.

All these on the net say that the 540 is unusable,but is it? http://www.chevelles.com/forum/biggrin.gif nope.