421 stroker?
Being bore limited is what kills the idea with a 427. I've done tons of research trying to figure out the beat way to do it. With being stuck to a 4.060 bore at best, the valves are still too shrouded to make any good HP. You will be way down when comparing it to a 427 with a 4.125 bore. The best bet I've come to figure ( and will be trying) is a 355 with 6.125 rods. Heads haven't been decided yet due to trying to plan the budget, but I'm thinking trick flow 21* will end up on it, but I'd love to throw some 18* heads on it and spin, but the funds would never be there. If we can ever get someone to produce a big bore block then you will see guys really making big HP with LTx's, until then go FI
We don't need more stroke, we need more bore.
All the badass SBC heads we have at our disposal require big 4.150+ bore diameters that we can only dream of.
What's the point of a 420+ CI shortblock when its a tiny ~4.060 bore and there are no ideal heads to put on it?
All the badass SBC heads we have at our disposal require big 4.150+ bore diameters that we can only dream of.
What's the point of a 420+ CI shortblock when its a tiny ~4.060 bore and there are no ideal heads to put on it?
^^This.
From another thread:
He went 9.98 @ 137 1.47 60' All Motor 3730 lbs on that setup. Dont know where he is now though.
I was talking to a friend of mine whos family is into late model dirt track racing, and he said some guys use the SB2s but they have found that 13 degree brodix heads will make the same power, but dont require you to spin it to 10,000rpm to get it. They get all their parts cheap too, I think if you searched around and found a good spot to find late model parts, you could pick up a set of assembled 13 degree Brodix heads for less than what you would pay for a fully hogged out AI TFS head, and flow at least 350cfm. There is actually a set of assembled SB2.2s on ebay right now for $2100 and it only costs $400 to convert them to reverse flow from CFM Motorsports (I think thats the name) Hes going to do some digging and asking around for me, not that I can afford this now, but Im kinda stuck on this daydream right now...
Also saw a few people knocking this idea on the impalass forums, saying that the intake, valve covers, and headers would surpass the 21 degree heads moneywise, but just use the intake and valvecovers the late models use, with the intake having bungs for injectors welded in and the thermostat and distributor holes welded closed, the same as all the single plane LT1 guys do anyways. Yes headers would be a bitch.
I don't know. I'd like to make as much on the motor this year as I made on a 225 shot last year. That would take about 730-750 at the crank. I think it'll make at least 700 at the crank. Depends if I sized the cam correctly for the compression. The cam is a cam motion sr 270/279 @.050 .720/.680 113lsa. Compression is about 12.5-1. I might be a little small on the throttle body. I have a 1250cfm but I should have a 2000cfm. I wanted it to have throttle response.
Of course I forgot to mention the motor is built for a 400 hit and I have a straight discharge direct port NX system capable of that and then some. I thin I'll need a progressive controller though......
Of course I forgot to mention the motor is built for a 400 hit and I have a straight discharge direct port NX system capable of that and then some. I thin I'll need a progressive controller though......
On the surface the 287cc ports do look way too big but the architecture of this head is different. The intake ports are substantially longer than traditional designs.
I agree that they are a little down from what they could be. The porting was done by a cup team. We flowed them on a 4" bore fixture so that didn't help the numbers. Plus these may have been busch or restrictor plate heads. I had the option to do some more port work but elected not to as the flow is well within my power range goal. Usually you will see 400-410 intake from a cup head.
I'll have some more work done to them next year when I build the big thumper turbo motor
I agree that they are a little down from what they could be. The porting was done by a cup team. We flowed them on a 4" bore fixture so that didn't help the numbers. Plus these may have been busch or restrictor plate heads. I had the option to do some more port work but elected not to as the flow is well within my power range goal. Usually you will see 400-410 intake from a cup head.
I'll have some more work done to them next year when I build the big thumper turbo motor
I was talking to a friend of mine whos family is into late model dirt track racing, and he said some guys use the SB2s but they have found that 13 degree brodix heads will make the same power, but dont require you to spin it to 10,000rpm to get it. They get all their parts cheap too, I think if you searched around and found a good spot to find late model parts, you could pick up a set of assembled 13 degree Brodix heads for less than what you would pay for a fully hogged out AI TFS head, and flow at least 350cfm. There is actually a set of assembled SB2.2s on ebay right now for $2100 and it only costs $400 to convert them to reverse flow from CFM Motorsports (I think thats the name) Hes going to do some digging and asking around for me, not that I can afford this now, but Im kinda stuck on this daydream right now...
Also saw a few people knocking this idea on the impalass forums, saying that the intake, valve covers, and headers would surpass the 21 degree heads moneywise, but just use the intake and valvecovers the late models use, with the intake having bungs for injectors welded in and the thermostat and distributor holes welded closed, the same as all the single plane LT1 guys do anyways. Yes headers would be a bitch.
Last edited by bufmatmuslepants; Feb 14, 2013 at 06:48 PM.
exactly ive found soooooo many heads i wanna run but they all have valves the size of small planets that wont fit in my bore without shrouding terribly.......next rebuild im going to look into what it would take to sleeve it.....im having pistons made anyway whats the difference if they're just made a tenth of an inch bigger lol
Years ago on cz28.com me and Warbird were talking about extending the deck of the LT1 by 2" by butchering an old block, welding it on then resleeving it to make a 427. Good times, crazy ideas. lol
Funny but isn't that what some of the aftermarket companies did to the LSX block?
Funny but isn't that what some of the aftermarket companies did to the LSX block?
exactly ive found soooooo many heads i wanna run but they all have valves the size of small planets that wont fit in my bore without shrouding terribly.......next rebuild im going to look into what it would take to sleeve it.....im having pistons made anyway whats the difference if they're just made a tenth of an inch bigger lol
I'd hate to dump a few extra grand into a motor only to see a water jacket leak into it or a sleeve shift.
Basically, what I'm saying is...you first :p.
In college I found an ANSYS report on Darton sleeves in an ls2 block with a 600 shot, those things are SOLID. You could probably bore the **** out of them and still maintain strength since you are NA
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