421 cube pulling truck engine

General engine tech -- Drag Racing to Circle Track

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randy331
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Re: 421 cube pulling truck engine

Post by randy331 »

CGT wrote: Tue Aug 07, 2018 10:56 am .... and I also would be reluctant to make real crazy changes to the valvetrain you have now, seems to be doing its job very well.
So how do you learn to walk if your afraid to take the first step? :D LOL

I was meaning valve events for the most part. Valve train does seem to be realativly happy as long as it stays off the rev limiter.
So,... If I made a cam change I'd stay with the same lobe family most likely.
Just wonder if a little later IVC or a bit earlier IVO may help it some past peak???
I do have 1.7 rockers for the ex too I could try. Ex has 1.6 on it now.

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Re: 421 cube pulling truck engine

Post by CGT »

randy331 wrote: Fri Aug 10, 2018 9:47 pm
CGT wrote: Tue Aug 07, 2018 10:56 am .... and I also would be reluctant to make real crazy changes to the valvetrain you have now, seems to be doing its job very well.
So how do you learn to walk if your afraid to take the first step? :D LOL

I was meaning valve events for the most part. Valve train does seem to be realativly happy as long as it stays off the rev limiter.
So,... If I made a cam change I'd stay with the same lobe family most likely.
Just wonder if a little later IVC or a bit earlier IVO may help it some past peak???
I do have 1.7 rockers for the ex too I could try. Ex has 1.6 on it now.

Randy
Pull it a couple thousand past peak on the dyno. Tune from that.
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Re: 421 cube pulling truck engine

Post by randy331 »

CGT wrote: Sat Aug 11, 2018 12:12 am Pull it a couple thousand past peak on the dyno. Tune from that.
Not sure how much you could find up there without hurting it at and a little under peak HP.
It currently doesn't seem like it's short on over rev abilities, but a higher gear would change that too.
I did make the dyno pulls too low of rpm I think. I wanted a good power curve as the engine got pulled back down through the rpm range, but it's never really been pulled back below peak HP so far.
More traction would pull some rpm out of the engine too, but not sure how to do that.
We put 2 different tires on the front for the Grant City pull and we won it and it seemed to make a good pass, but we were pulling against trucks we haven't been pulling with so it's hard to compare.

One thing I'd have liked to see this year is just how much more gear would it take to gut the engine. Last year after He closed the front diff, it gutted Tommy Boy at every pull after that. It made 500Lbs and 630ish HP and it was ran with a 28.8 final. This year we have a 27.06 final and have put taller tires on it and it has yet to gut it once and we've been on some very well preped tracks, so I'd like to know how much higher gear it'd take to gut the 421 ? It would give us some info on gear choices for different power levels for future engines.

Boone said after the season is over he's gonna borrow the cut tires off his brothers Pro Mod truck and put on his truck and go to a brush pull. That should gut his, or break some drivetrain parts. LOL
Boone is goin to the State Fair, there will be some good trucks there. That will tell us something .


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Re: 421 cube pulling truck engine

Post by RevTheory »

Sorry for the newbie question but does "gut the engine" mean it gets dragged down to an rpm where power falls and it can't recover?
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Re: 421 cube pulling truck engine

Post by randy331 »

RevTheory wrote: Sat Aug 11, 2018 10:37 am Sorry for the newbie question but does "gut the engine" mean it gets dragged down to an rpm where power falls and it can't recover?
:)
Yes, pulled backwards down through the rpm till lights out or you have to clutch it to keep it running.
I guess "gut the engine" must be a truck puller term. :)
I guess in drag racing " gut the engine" may mean a track clean up. :lol:

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Re: 421 cube pulling truck engine

Post by speedtalk »

randy331, sorry to lock this thread. Please feel free to start a v2 thread.

As for the person mentioned in now deleted posts.

1) About a month ago he asked me to delete his account - said he was leaving ST. He was mad that I had "liked" someone's comment that called for civility. Apparently, taking my "like" as an endorsement of that person's other comments -- which is myth #1 on this forum.

2) About a week ago he sent me an email stating he was holding me personally responsible for anything said about him on ST. It sounded angry, even one step from violent. I did a search of his name and did find negative threads/comments. I was actually surprised that they hadn’t been reported. So, I did some deleting and worked to make sure no comments were made about him. Perfect solution? No, I wish there was one.

I don’t know, maybe he has some issues in his personal life that are the source of the anger — issues I would have even been sympathetic to. But, when someone reaches this level of incivility, it’s time for them to find another forum. I think he knew this when he asked to have his account deleted.

I started ST 15 years ago. Has everything I've done been the best course of action? Most assuredly, not.

I know there’s a fair chance I could have diffused this issue had I intervened early. But, I’ve been dealing with some health issues that have kept me distracted, so I kind of left the forum to police itself. Which had worked surprisingly well.

I’m back now and taking a more active role. Hopefully you all can help me return ST to what it has been best known for — its civility.
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