4.1 stock block build

Yes Trend is local to me and good friends of ours. I had to deck this block to square it so the pushrods ended up 7.925" these are the .105 wall with .210 tapered ends
 
Thanks for pointing out the obvious. Maybe I should have been more specific...

If I remember correctly Mike this particular block (casting number) has a thicker deck and more material around the water jackets however the block will still hold together? My understanding 109 don't last too long when spun to 6k.


Walter
 
Oh yeah!! Check my previous posts. Because of tranny issues, my old stock block 4.1 saw 6800 & 7400 RPM!!! Handled it lke a champ & ran for years after.
 
The block I am using is the 484 which is reported to be not as good as the 291, the 484 has the oiling updates and at least this one had very good (thick) cylinder bores. So I dont see a problem with it. A steel crank really helps everything since they don't flex like the stock one does. I have a couple main caps too. I would have no problem running this one at 6500+ but like someone said above detonation is the the killer and the higher the RPM the more it kills. Properly prepped 109 blocks will spin well over 6000 reliably but sinc the mindset is to use small cams there is really no need. Bigger cams and more RPM will make a lot more power but when it breaks the combo of more power and RPM will likely make it a bad one, there is no free lunch.
 
so the champion ported stock intake is on, with the Hemco plenum, and GN1 headers, not pictured is the 120LB injectors and the throttle body. It is ready to go into the car and will likely today. There has been lots of discussion on those headers so I thought I would try then. I had a set on the shelf from a customer who returned them after reading here. He never even opened the box to look at them. They bolted right on, no problem I went to put the crossover on and it did not fit, dammit, I was sitting and looking at the engine on the stand and decided to loosen up the bolts that hold the headers to the heads and move them a bit, bingo the crossover fit perfect and everything lines up. Since they use CNC v-bands instead of ball joints they are picky about alignment but that problem is solved hopefully someone having a problem will read this and it will help them. I am pretty excited about the throttle body. One of my friends had one of the 62MM throttle bodies we used to do, it was actually the second product we ever made, I think we started in 90 or 91 doing those, and this one has been in his garage for years. He sold it to me, so it is great to have one of our original parts on this car. Marianne's dad was a boring mill guy and made a fixture to machine them I had Kinsler make the special oval blades. May not seem like much to you guys but it was one of the things that really took off at the time and helped us start the business. I am proud to run it.
 

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Mike Licht said:
...I am pretty excited about the throttle body. One of my friends had one of the 62MM throttle bodies we used to do, it was actually the second product we ever made, I think we started in 90 or 91 doing those, and this one has been in his garage for years. He sold it to me, so it is great to have one of our original parts on this car. Marianne's dad was a boring mill guy and made a fixture to machine them I had Kinsler make the special oval blades. May not seem like much to you guys but it was one of the things that really took off at the time and helped us start the business. I am proud to run it.
Click to expand...


You sure you don't need some 90mm TB on their? JK...;)
 
that was my plan but I had the headers and I was able to trade a customer some parts for a an older cast wheel 7480 (which makes about the same rated power as a 6766) so this was in my budget. I am going to switch out to some 4 bolt headers and a new turbo that is in the works later, this will give us a yardstick to show the potential of the 4 bolt set up
 
I won't go back to a 3 bolt. The 4 bolt housings are great on the street and I could be running a lower stall converter without hurting spool up. You won't be disappointed.
 
Looks good Mike. Are the 3.8 and 4.1 front covers the same? What's your ETA on taking 4" piston orders? Thanks
 
the aftermarket covers work on both GM covers are different. We can take 4" piston orders now, after I get it running we will have them in the building. Steve and I are going to drop it in the car this afternoon
Mike
 
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