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The 454 that is in my friend Mark's gold 69 SS came out over the winter for a little freshening up.
Car ran a best of 13.30 @98 MPH with a 1.81 60 ft.
Combo is a rebuilt 454 from chain parts store,nothing special.
When Mark bought the motor,it was never fired,still in the shipping crate from the parts store
Typical 8 to 1 compression,781 heads.We added a Summit 238/248 @.050 .540/.540 114 LSA cam,3310,RPM Air Gap,small tube headers,2.5" exhaust,11" 2400 stall,3.07 gears (and it runs on 87 octane)
We always wondered why the car would never MPH higher than 98..car felt real strong on the street and would 60 ft. pretty well for 3.07 gears in a heavy car with a more or less stock 454
We discovered #3 intake valve was not sealing very well..compression was about 80-85 lbs. in that cylinder.Figuring it never sealed right after whoever did the heads.Guessing Recon or one of those places.
So,we pulled the motor and picked up a pair of mildly worked 215 casting closed chamber heads that have 2.19 intakes added and the stock 1.72 exhaust.FWIW,Mark bought the heads from a fellow TCer (thanks Gary/gnunzio) and they had made 400 HP on his 402 with a Comp 270H and the low rise cast iron intake.
We also discovered the 454 motor is .060 over and had Speed Pro hyper flat tops in it.
Its all buttoned up,back in the car and we got it running tonight...sounds better than it ever did.All timed at 20* base and 36* total by about 2800
Also,the car now has 3.42 gears and custom built Dynamic 10" convertor that flashes to 3400-3500..we are figuring with a full point more compression,all 8 cylinders firing happily,more gear/convertor it'll do better than 13.30 @98 MPH :D ;)
I will post dragstrip results..our track doesn't open until April 10th..unless we hot foot it on down to Englishtown.Have to get my 70 back to the track since the convertor swap too.
Tomorrow,hood goes on and then hopefully a test drive or two :thumbsup:
Anyway..thanks for reading :)
 

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That's a lot of changes, more of a matched combo now. I think you will see a significant change. Typically, the rebuilders cut the valve seats and resurface the valves, but never lap them to check fit. Especially is a guide had been replaced in the head, it can end up off center, doesn't take much. Just for info sake, would be interesting to lap that one valve/seat and see how far off it is. Could even be a bent valve. Be nice to keep those 781's for when he wants the next leap (it happens to all of us).
 

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Did he decide against the 60203?
 

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Dan...he wanted to leave the Summit cam in there.He has the old mindset if it ain't broke..
Probably not a bad idea because now you will see what improvement the heads made. Maybe you will talk him into the cam later.
 

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Real curious Chris to see how this works out. Love this before/after stuff. I plan of hitting the track myself this Fri night, suppose to be 70*+ and sunny. I replaced the solid rollers with Morels hyd's - let's see if they can match the hype.
 

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I bet it will be in the 12's. A bad sealing intake valve really hurts power. The additional compression ratio should really help too, not to mention gears and converter.
 

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does it still have the vs carb on it ? one would think he'd upgrade to a dp, and a bigger/better bumpstick to go with the better airflow, gears,looser converter, and 9 to 1 comp
 

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The 454 that is in my friend Mark's gold 69 SS came out over the winter for a little freshening up.
Car ran a best of 13.30 @98 MPH with a 1.81 60 ft.
Combo is a rebuilt 454 from chain parts store, nothing special.
When Mark bought the motor, it was never fired, still in the shipping crate from the parts store
Typical 8 to 1 compression, 781 heads. We added a Summit 238/248 @.050 .540/.540 114 LSA cam, 3310, RPM Air Gap, small tube headers, 2.5" exhaust, 11" 2400 stall, 3.07 gears (runs on 87 octane)

We always wondered why the car would never MPH higher than 98.. car felt real strong on the street and would 60 ft. pretty well for 3.07 gears in a heavy car with a more or less stock 454
We discovered #3 intake valve was not sealing very well.. compression was about 80-85 lbs. in that cylinder. Figuring it never sealed right after whoever did the heads, Guessing Recon.
So, we pulled the motor and picked up a pair of mildly worked #215 casting closed chamber heads that have 2.19 intakes added and the stock 1.72 exhaust.FWIW, Mark bought the heads from fellow TC'er (gnunzio) and they had made 400 HP on his 402 w/a Comp 270H and low rise cast iron intake.

We also discovered the 454 motor is .060 over and had Speed Pro hyper flat tops in it.
Its all buttoned up, back in the car and we got it running tonight... sounds better than it ever did.
All timed at 20* base and 36* total by about 2800
The car now has 3.42 gears and custom built Dynamic 10" convertor that flashes to 3400-3500..
we are figuring with a full point more compression, all 8 cylinders firing happily, more gear/convertor it'll do better than 13.30 @98 MPH :D I will post dragstrip results..;)
Tomorrow, hood goes on and then hopefully a test drive or two :thumbsup: :)
that comp. test is only relative to a Mopar 440 wedge.. totally different than a big block Chevy.

The open chamber big block heads make more power w/lower compression according to the old Chevy engineering data.
Case in point ...
71 LS5 454 /365 HP 8.5 to 1
70 LS5 454/360 HP 10.25 to 1 ... both motors used the same cam.
I'm curious, would you expect the 1+ extra point in compression to overcome the "power loss", from swapping the #781 open chamber head -to- the #215 closed chamber heads, if the valve sizes were equal ???
 

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Discussion Starter · #15 ·
I'm curious, would you expect the 1+ extra point in compression to overcome the "power loss", from swapping the #781 open chamber head -to- the #215 closed chamber heads, if the valve sizes were equal ???
is that a gearhead conundrum ? ;) :D
I don't like to speculate.All I know is,the motor is in a little bit better shape output wise.
 

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should be interesting. Good luck!
 

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Discussion Starter · #17 ·
Spent some time as a passenger in it today as well as driving it...car feels great..awesome throttle response and no traction as expected.Behaves the same as before..just feels a little bit snappier and sounds deeper in the exhaust.Compression test revealed 150-155 lbs. versus 130-135 lbs. with the open chamber heads.Still runs on 87 octane too!
 

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This is a similiar build to mine. Whats it sound like? Any sound clips? I think I might have this same cam in my engine that I have yet to fire as I bought the car minus a few parts. Does it have a decent sounding idle for a small cam? Im on the fence if I should tear a good running engine apart this season or wait till this winter to make my changes. Thanks!!
 

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I am thinking 12.70 @ 104-105 MPH

Id guess it has more like 107-108 MPH and bottom 12's in it unless he is real heavy. You figure, about the only thing it is somewhat lacking is compression. The compression isnt even bad, but 10:1 would probably be a nicer figure if building from scratch.

I guess depending on how small the "small tube" headers are....that may factor in a difference, combined with the smaller, stock exhaust valve too. As long as the small tubes arent too small...I doubt its way down on horsepower.
 

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12.6 @106 since we're guessing....
 
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