Bigger intake smaller exhaust valves

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canuc
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Re: Bigger intake smaller exhaust valves

Post by canuc »

What about a 2.00 with 50* seat ? Did you have a casting picked yet ?
Little Mouse
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Re: Bigger intake smaller exhaust valves

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Being as I'm nuts enough to want to do a 3.00 stroke and I have a very light set of 6.250 rods that are 507 grams. I'd say I'm going to have to lean torward using one of darts 49cc chambers, even then I'm going to have to come up with a tiny size dome.
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Re: Bigger intake smaller exhaust valves

Post by swampbuggy »

What fuel are you planning on Little Mouse ? Mark H.
canuc
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Re: Bigger intake smaller exhaust valves

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Little Mouse wrote: Sun Mar 29, 2020 8:13 pm Being as I'm nuts enough to want to do a 3.00 stroke and I have a very light set of 6.250 rods that are 507 grams. I'd say I'm going to have to lean torward using one of darts 49cc chambers, even then I'm going to have to come up with a tiny size dome.


how much cr do need ? small.chamber with angled spark plugs right at the roof don't have any issue with a low dome .
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Re: Bigger intake smaller exhaust valves

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That's it in a nut shell at first I thought I'll run all the compression i want with the street car and just do E85 fuel but now ive talked my self into regular pump gas and losing out on the compression.
But id like to do two new edlebrock AVS2 650 carbs so for sure cant do E85 with them. Have not bought the crank I could do a 3.25 stroke and make it easier to use all the more common 64 cc aluminum heads of which I would probably buy profilers. If money were no real object id buy the comp version of afrs 195. I have this deases that likes the best bore to stroke ratio on anything. Lol
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Re: Bigger intake smaller exhaust valves

Post by mag2555 »

If you want to make big power numbers at high rpm from a small cid motor and not be taring it down every other Month to inspect it, if not freshen it up then besides air flow numbers you need to think about fictional hp reduction and light valvetrain parts from the rocker to the retainer, valve spring and valve.

Your really not breaking any new ground here by building a very high rpm motor' so I can't make any logic out of why you seem to refuse to take a easier route to the same power levels with less cost and greater longevity!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
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Re: Bigger intake smaller exhaust valves

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The logic Mag2555 is.........There is just something about the sound of a SBC or SBF for that matter after it gets to 8000 or more, the sound is high quality music to a discerning pair of ears !! :D :wink:
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Re: Bigger intake smaller exhaust valves

Post by mag2555 »

Then go to a NAscar oval track on race day and record some live audio of those 9000 rpm motors and blast it back thru your cars stereo whenever your motors rpm gets above 6800.

Your wallet will love ya for it, lol!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
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Re: Bigger intake smaller exhaust valves

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mag2555 wrote: Mon Mar 30, 2020 6:56 am If you want to make big power numbers at high rpm from a small cid motor and not be taring it down every other Month to inspect it, if not freshen it up then besides air flow numbers you need to think about fictional hp reduction and light valvetrain parts from the rocker to the retainer, valve spring and valve.

Your really not breaking any new ground here by building a very high rpm motor' so I can't make any logic out of why you seem to refuse to take a easier route to the same power levels with less cost and greater longevity!
Yep and original 302 that I had in my new 69 Z/28 that I put 36000 miles on before I got corvette fever I think the factory rods were around 600 grams the piston was an unreal 1.80 compression height think they were probably around 547 grams the the long pin heavy. Rings heavy high in friction. Im going to use 507 gram rods 6.250 in lenght rods
have those, with light pistons small friction rings No more then 2.5 long pins. No matter 302 or 327 it will have a solid flat tappet cam the spring I have my eye on is a single conical 130 seat 400 open with a good amount of rate it will be light and I'll buy tool steel retainers. Not going to do a drag race rate cam or real high lifts will no doubt be high in duration that most people would not want in a street car. Just because something can do high rpm does not mean it has to be run that way all the time like a race car. Been awhile but I owned 2 new Camaro and 4 corvettes two of the vettes were ordered new 1 of the camaros I ordered. I've had 454 a 396, 302, 331, countless 350s and helped build for a friend a 400 sbc he raced some in his 69 camaro, the shop we rented together at the time I had a 66 vette it used both the 331 and 396 in it. Owned a bunch of fast motorcycles for there time period. But in 2018 bought a new 1200 triumph bonnevile thats what I wanted could have easily bought another much faster motorcycle. All I would like to do isq small bits to make a 302 for the fun factor to make it both reliable and decent power for what it is. Not going to try to rotate the earth on its axis with a 302 chevy. Lol my 454 turned almost 8000 rpm so did my 302, 331, 396 back in seventies with factory parts heavy trw pistons. 8000 rpm today street or race car is baby shit. Stiff valve springs are what does not last that roller cams need unless mild. My only experience with them was in another 331 when you had nothing more then bronze dist. Gears to use. I had a 454 4 bolt block that orignally came out of a friends 450 hp LS6 chevelle. Sold it only 6 years ago to a friend wanted it but I kept three sbc blocks. I have no doubt could have made more power with it then a 302. If I still had that bbc I swear on a stack of bibles instead of the common 4.250 stroke aftermarket crank I would be hunting down a forged 3.25, 348 crank to use if I can figure out a good way to do the smaller mains. I also had two brand new steel chevy 427 cranks I sold with the 454 block.
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Re: Bigger intake smaller exhaust valves

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I was just thinking that if I'm not doing roller cam valve lifts for area that a bigger valve opening would be some help. But its morphed into build a 496 or better yet a 632 or go to sonny's and get that 1000 cube engine.
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Re: Bigger intake smaller exhaust valves

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I could forget about the 302 and do a ricer vette. Take an an all aluminum honda 4 that does 9000 rpm ad a bit more hp to it. Both engine and trans needed would be lighter probably drop 275 to 300 lbs off the car. Would be almost worth it to see the look on vette lovers face with the hood open. should be easy to set the engine and trans further back in the car.
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Re: Bigger intake smaller exhaust valves

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Then you would have to hang out with the teenagers LOL :lol: Mark H.
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Re: Bigger intake smaller exhaust valves

Post by JodyB »

So...., instead of sinking all this effort into a 302, why not just build an underperforming 350 to accomplish the same torqueless performance and high rpm. Low C.R. and huge solid cam. Done. Lol
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Re: Bigger intake smaller exhaust valves

Post by canuc »

I've got some fond memories from the 70's with the gutless little 302 . What I recall was the lack of torque with decent horsepower actually worked well in a 69Z . Engine was responsive to available hotrod parts and with only a set of 5.13's and some lakewood lift bars the car was fast around town with H60-15 tires and could still go around a corner . That gutless little 302 just hooked and left the big blocks with the N50's trying to get traction .
Little Mouse what car were planing your engine for . I still plan on building a couple 306's I have most parts for . I have a roached x77 I bought 20 yrs ago that hope to build after I retire to home , hopefully soon . So I'll follow your rambling with some interest .
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Re: Bigger intake smaller exhaust valves

Post by Tom Walker »

I am with you Little Mouse, build it the way you want. If we took logic and practically into consideration, most of what we do would be curtailed or eliminated.
We do it to create that feeling of accomplishment and satisfaction that suits our own unique desires.Live your dreams, now back to my Z28 with too much cam, too much gear and obnoxiously loud. It's a blast!
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