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Good and bad story............I assume you squeeze this thing?

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Ran a 10.50 @ 120.77 at Speedworld on Saturday. Yes, only 120. 1.44 60 foot. Lost 2 plugs in high gear when the ground straps melted off. Damage accessment to follow.

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Good and bad story............I assume you squeeze this thing?

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Yep.

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Oh, THAT kind of squeeze..............hope there`s not much damage for you.

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Ran a 10.50 @ 120.77 at Speedworld on Saturday. Yes, only 120. 1.44 60 foot. Lost 2 plugs in high gear when the ground straps melted off. Damage accessment to follow.

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Hopefully you got lucky. My 340 always got a piston or a head gasket. Since I reduced my timing (1991) to 30 total it 's never hurt itself again at12lbs boost.
Doug

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Ran a 10.50 @ 120.77 at Speedworld on Saturday. Yes, only 120. 1.44 60 foot. Lost 2 plugs in high gear when the ground straps melted off. Damage accessment to follow.

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Hopefully you got lucky. My 340 always got a piston or a head gasket. Since I reduced my timing (1991) to 30 total it 's never hurt itself again at12lbs boost.
Doug

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Same timing I was running. Unfortunately, a little more boost - 25 psi.

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This is one of the reasons I run N/A. I can barely tune my heap let alone nos or blower stuff......... When you gonna tear into it?

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Ran a 10.50 @ 120.77 at Speedworld on Saturday. Yes, only 120. 1.44 60 foot. Lost 2 plugs in high gear when the ground straps melted off. Damage accessment to follow.

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Hopefully you got lucky. My 340 always got a piston or a head gasket. Since I reduced my timing (1991) to 30 total it 's never hurt itself again at12lbs boost.
Doug

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Same timing I was running. Unfortunately, a little more boost - 25 psi.

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This is one of the reasons I run N/A. I can barely tune my heap let alone nos or blower stuff......... When you gonna tear into it?

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Probably tomorrow. I had no business running that amount of boost. Stupid me!! Ran with the wrong size pulley on the blower for the rest of the set up. All I needed to do was run the larger blower pulley with the CORRECT belt tension. One thing about drag racing - when you do stupid stuff, you always pay.

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I'd do a compression check. If its good then go a range colder on the plugs, back the timing back five to seven degrees and depending on A/F fattin it up a couple jets and try again. Once its dialed in for hi boost it's time to play!

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I'd do a compression check. If its good then go a range colder on the plugs, back the timing back five to seven degrees and depending on A/F fattin it up a couple jets and try again. Once its dialed in for hi boost it's time to play!

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Ya,all the above. Just ran a comp test and all appears good (within 2 lbs from previous test on all holes ). Valve train all looks good, including lash. Attached pic of plugs - NGK ZFR5F. Two burned ones were in holes 4 & 5. I'm open for suggestions on plugs? Could go a few steps colder - or maybe something that isn't an extended core? Already 5 sizes bigger on the jets all around - as I received the blower carb from ProSystems ( annular discharge 950 ). I could use some help with plug selection ( 408 blower motor with ported Magnums ).

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Go to the race plugs first off. Start with a plug on the colder side and go from there. Does not look to bad do as fastmop suggests and get after it.

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Put the biggest nozzle in the meth inj. Run a ngk 5671-9 or 10 and let her rip. 11.8-12.0 is a good afr to shoot for on a blower motor.

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I've read alot of bad things about running meth if you don't have almost perfect distribution across all the intake runners...don't know this from experience though. As for the wideband, I've got a LM-2 Innovate and I love it. It kept me from pulling my hair out trying to get a good safe tune. I run 93 pump (E10) on the street and 100LL avgas when I want to set it on kill. I've been as high as 18lbs with cast pistons and avgas, would have never felt safe doing it without a wideband

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I've read alot of bad things about running meth if you don't have almost perfect distribution across all the intake runners...don't know this from experience though. As for the wideband, I've got a LM-2 Innovate and I love it. It kept me from pulling my hair out trying to get a good safe tune. I run 93 pump (E10) on the street and 100LL avgas when I want to set it on kill. I've been as high as 18lbs with cast pistons and avgas, would have never felt safe doing it without a wideband

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I'm suprised you didn't hurt it worst than you did with that hot of a spark plug your lucky iit only burnt the ground straps off I would go to a non protruded gap and a #9 or#10 as already suggested. The last blower motor I work on dyno testing was a 484 C.I. 426 Street Hemi, it liked 33 degrees with 7 lbs of boost using a 10:71 Littlefield roots, no intercooler, running 12 % under on CA pump gas, that combination made 927 HP at 7300 RPM after doing a lot of small changes on it to sneak up on what it wanted. We got greedy (the owner wanted more) and switched the pulleys around to make it have 13% overdrive, switch it to race gas, back the timing down to 25 degrees total and made another pull, it started into detonation slightly at 6500 RPM and still made 1027 HP at 6500 RPM (we pulled it to 7500 RPM on all the pulls except the last one) I moved the timing up to 28 degrees total and ended up aborting the run wjhen it started to go into detonation again Luckily it didn't hurt it I switch the pulleys back and told him when you get it to hook up with the pump gas combination call me and we would hop it up again,I never got that call My meassage is back that baby down some to be safe and then sneak up on it Maybe some day, if I ever when the lottery or my ship comes in, I'll try a compressor on some of my own junk, twin hair dryers with intercooling and EFI

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As always, thanks for the info Cab. Definitely making a plug change and going back to the 4" blower pulley ( from the 3.7" ) until I can get a handle on it.

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Thats a good looking boat you have... and runs well...
hopefully its got 2 straps stuck in a couple of pistons
and didnt hurt it

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Thanks Mike - - I think . Now I gotta find someone who has a boriscope .

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Looks like you got lucky.
I've lost the straps a couple of times over the years. It never did any more than put some little pits into the top of the piston or head... and sometimes they rattle around and into an adjacent cylinder to rattle around before spitting out the exhaust too! LOL

When I tore mine down after quite a few miles and "incidents" like that (unintended overboost - followed by detonation), I did notice that the top of the rod bearings were showing their discontent. Clean up the tops of the pistons and get a new set of bearings and it's all good!

That's WAY better than the trip to Speedworld where I blew a quarter-sized hole dead center in the top of one of the pistons! hehehe

Ground straps? No big deal.

I'll watch for you out there!

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Hey Blaine, just ordered some race plugs per NGK techs suggestions. R5671A-7 for 10-15 lbs boost and R5671A-8 for 25 lbs boost. CU at the track

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I've got a scope down at the shop John. Come on by and get it.

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Thanks big D, but probably be cheaper for me to just go borrow my proctologists scope.

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Looks like you got lucky.
I've lost the straps a couple of times over the years. It never did any more than put some little pits into the top of the piston or head... and sometimes they rattle around and into an adjacent cylinder to rattle around before spitting out the exhaust too! LOL

When I tore mine down after quite a few miles and "incidents" like that (unintended overboost - followed by detonation), I did notice that the top of the rod bearings were showing their discontent. Clean up the tops of the pistons and get a new set of bearings and it's all good!

That's WAY better than the trip to Speedworld where I blew a quarter-sized hole dead center in the top of one of the pistons! hehehe

Ground straps? No big deal.

I'll watch for you out there!

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Hey Blaine, just ordered some race plugs per NGK techs suggestions. R5671A-7 for 10-15 lbs boost and R5671A-8 for 25 lbs boost. CU at the track

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I would put a -9 or -10 for 20+ lbs. of boost, never a -7 or -8 heat range plug I run -7 and -8 in my pump gas low compression street motors at 14.2 AFR and leaner at idle and part thottle AFR

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We run a -9 with 15-16psi and 8.8 static compression. 406 cu in small block.

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Decided to go with 8's & 9's.

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Thanks big D, but probably be cheaper for me to just go borrow my proctologists scope.

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That is one great running "land yacht". If I wasn't so old or stubborn I would love to play with a power adder. I would probably have to go the procharged route as I still love the competition of racing and I think that makes a more consistent combo. Maybe someday but nitrous will never touch one of my cars.

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This blower motor is a big learning curve for me right now, which equates to - not very consistant. Just hope I don't "step on my crank" too severely while I'm going to school .

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That's why I would not be making too many changes to what you have. Those plugs are real close to being spot on. You should really only make one change at a time. If it was my car I'd swap plugs and make a pass to the shift into hi gear. Turn it off and check them. Adjust the tune up in baby steps to dial it in. Then I'd detune it a little with a little less timing and try to enjoy beating on it for a few years

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You been talkin to my wife??? I got the same speach this morning!

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The bigger pulley will be your detune.

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Already on - along with NGK # R5671A-8's gaped @ .030". Think I will drop the timing back to 28 ( I was running 30 ) also. Hoping these changes will net me a clean run. Appreciate everyones input on this thread.

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Will help for vids!

So when you getting back out?

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Will help for vids!

So when you getting back out?

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Not for a couple of weeks.

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Well, got out to the track yesterday and finally made one clean pass and ran a 128.70 MPH. Unfortunately, track prep was poor and couldn't get out of the 1.50 range for 60 foot times, so only ran a 10.60 et. Next run lost the alternator belt, which took out the blower belt, which took out a trans cooler line, which promptly ended my day and shut down the track for a 45 minute clean up session. I did not get off the track as soon as I could have and I don't feel too good about that. Belt came off just before the lights ( ran a 126 on that pass ) and had my hands full getting it stopped with trans soaked tires.

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If is wasn't for bad luck you wouldn't have any luck at all. See you at Firebird next week.

Raul

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It's on my schedule Raul, but doubt I will be able to make it. Haven't assessed all the damage yet. Still playing "clean up in isle 5".

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If is wasn't for bad luck you wouldn't have any luck at all. See you at Firebird next week.

Raul

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It's on my schedule Raul, but doubt I will be able to make it. Haven't assessed all the damage yet. Still playing "clean up in isle 5".

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Time to take a break and look everything over very carefully More Power, more and quicker problems harder to fix, you've been lucky so far get the fine tooth comb out

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If is wasn't for bad luck you wouldn't have any luck at all. See you at Firebird next week.

Raul

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It's on my schedule Raul, but doubt I will be able to make it. Haven't assessed all the damage yet. Still playing "clean up in isle 5".

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Time to take a break and look everything over very carefully More Power, more and quicker problems harder to fix, you've been lucky so far get the fine tooth comb out

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Your on the money there Cab. Gonna go over my whole program in the next few weeks. Think I'll start by changing gears ( 4.56 to 4.10 ) to try and slow things down a bit. As it is, if the car doesn't hook real good, I end up going through the lights at around 7500 - which is part of my belt issues. The plug change I made solved the melting ground strap issues anyway.