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hiya everybody
i have a 1964 Impala 2 door hardtop
i'm working on a 1983 low milage 454.
i wanna know if the following parts will work together:
LS-7 pistons
236 peanut heads
crower 01904 cam
also what stall speed for a thm 400?
a 3.25 to 1, 9 inch is already installed
thanks so much:D
Please be more specific. There was a LS7 454 produced 1970 & 1971 and there was an LS7 427 Z06 produced for the Corvette in recent years. The 454 LS7 pistons will be the proper diameter to use in your motor, but the generous dome on them will not be compatible with today's pump gas. They will produce a static compression ratio that will be too high and will cause detonation. When the original 454 LS7 came out, there was 100+ octane pump gas available on every other corner. The bore of the late model LS7 427 is only 4.125", so that piston will not work in the 454 bore.Quote:
Originally Posted by cribboy52
If I were to choose pistons for you to be used in a pump gas motor, I would limit the static compression ratio to something around 9.0:1 to a max of 9.5:1 static compression ratio. Current thinking limits iron heads to about 9.5:1 static compression ratio max and aluminum heads to about 10.5:1 max due to detonation problems at higher compression ratios using today's pump gas. I ain't what it used to be. :mad:
While these heads will work really well to haul most anything around town at "in town" engine speeds, they lack any definition of high performance and the cost to improve them is, in my opinion, voodoo economics. In some cases, bringing these old production heads into the 21st century will cost as much as opting for new aluminum heads. If you can't do any better than these heads, then use them, but don't expect anything spectacular from them. They will be great off idle and up to maybe 4000 rpm's, but will fade out in the stretch simply because they haven't the ability to breathe enough to feed 454 cubic inches at higher revs.Quote:
Originally Posted by cribboy52
Here's the skinny on 'em....
Intake runner volume 208 cc's
Exhaust runner volume 112 cc's
Intake valve diameter 2.06"
Exhaust valve diameter 1.72"
Combustion chamber volume 120 cc's
Flow in CFM @ 28 inches of water depression...
0.100" valve lift 56/44
0.200" valve lift 125/90
0.300" valve lift 183/117
0.400" valve lift 215/139
0.500" valve lift 233/158
0.600" valve lift 235/166
0.700" valve lift 235/172
These are numbers that would do well on a 350 Chevy in a moderate performance mode, so you can see that they are barely acceptable in a 454 street driver.
You can make this cam work, but you will have to raise the static compression ratio of the motor to 9.3:1 with this piston....Quote:
Originally Posted by cribboy52
Speed-Pro Hypereutectic Pistons H693CP30 - Free Shipping on Orders Over $99 at Summit Racing
With a 9.3:1 static compression ratio, the crower will produce 8.31:1 dynamic compression ratio and should run detonation-free on pump gas, together with a tight 0.045" squish afforded by a shim steel head gasket like this....
Mr. Gasket Head Gaskets 1131G - Free Shipping on Orders Over $99 at Summit Racing
You may want to read and re-read this tutorial several times. It explains the problems with using a standard hydraulic flat tappet cam in today's world....
http://www.crankshaftcoalition.com/w...ips_and_tricks
If I were going to build a street motor today, I would use a retro-fit hydraulic roller tappet cam. Howards has probably the best prices on these cams.
Next best thing over the standard hydraulic flat tappet cams would be a solid (mechanical) flat tappet cam with EDM holes in the bottoms of the lifter bodies to spray oil at the interface of the lifter and the cam lobe.
http://www.vintagemusclecarparts.com...ter_bottom.jpg
You can't do these holes in the bottoms of hydraulic lifters because the interior of the lifter is pressurized with oil to adjust the lash at the rocker arm/valve stem tip.
It's not the type of transmission that dictates the stall speed of the converter, it has more to do with the cam operating range and weight of the car.Quote:
Originally Posted by cribboy52
With this cam's operating range beginning at 2000, I'd go another 500 rpm's and choose a converter that stalls at 2500. It will be perfectly driveable on the street. I'd choose a 10" diameter converter rather than a cheezy 12" with the fins bent over. GOOD converters begin at about 350 bucks.
.
3963551 is the number stamped into the pistons, but it seems to be a moot point since they won't work
i have another set of slugs in mind which shud yield a lower CR.
will a 2200 stall work?
this is not going to raced but i do want it to perfrom better than a truck engine
thanks so much
the new pistons i'm looking at are sealed power/ speed pro H581CP.
the guy that has them says 236 heads with these pistons and steel shim shud give between 9.5 and 10 CR
My calculations result in a static compression ratio of 10.35:1. That would be great with aluminum heads, but I wouldn't use them with iron heads. Use at your own risk. The pistons I linked for you are only $263, so it ain't the end of the world.
will a 2200 stall work?
Any converter will work, it's just a matter of using one that will perform like you want. You know that the cam begins to make power at 2000 and you know that most everybody will counsel you to use a converter that stalls 500 rpm's over the low operating range of the cam.
I just realized that I made an error calculating the original SCR. With the H693CP30 pistons, SCR would be 9.67:1
I'd still use 'em.
.
thank you so much for all the help.
I will get back to you after I get the engine built.
good evening
hello again, i've acquired a new flexplate number SUM-G102SFI, and a 2500 stall converter. it measures 12 inches diameter. the bolt holes don't match. can i drill it myself or is a machine shop the best way to go?
thank you
My answer is "Neither." I'd return the one that doesn't match and get the proper flexplate or stall converter. You're dealing with critical, rotating equipment that's going to amplify any tiny differences into vibrations, which lead to cracking, which leads to failure. Just my $0.02 and others may disagree.Quote:
Originally Posted by cribboy52
I believe that your 454 is an externally balanced engine and if I'm correct you must have the flexplate that matches the crank. Pat McCarthy (bbc guru on this forum) will know for sure.
Another thought, the Gen1 bolt circle is a little bit different size from the Gen 3 & 4.... Is your issue with the flexplate or the converter, or both? Like Ken says, hopefully Pat can solve your mystery with facts.
that flexplate is for external balanced 454 except about half of the reviews on it complain about having to file the bolt holes and some about starter teeth breaking off----its listed as sfi approved but I highly dougt that as the price is pretty low-------design might be approved, but flex plate might not pass inspection
I read those reviews saying they filed the inside edge of the bolt holes too, and to me the question would still be "Did those guys have the right flex plate for their engine?" Of course at this point we don't know which piece has the "mis-match", or if it's both.Quote:
Originally Posted by jerry clayton
there were comments about non standard converters------ there are 3 and 4 bolt converters, some flexplates have 6 bolt holes which are 2 different 3 bolt patterns---most converter bolt holes are ob-long which allows some radial flex/heat growth
I think the different bolt patterns you refer to Gen 1, 3 ,4 are crank patterns
thanks everyone for the input.
the flexplate is brand new in the box.
I got it as part of a package deal with the pistons/wrist pins/rings.
the crank bolt pattern is 7 holes. 6 are equal spacing and the last one I assume is for correct positioning.
it has a counterweight welded to the plate.
it's zinc plated.
there are 6 converter holes which are oblong.
I bought it used. the seller listed it as 1500 miles of use on a 2500 stall converter.
it looks brand new and has 3 mounting bolt holes. it's 12 inches across.
I was expecting it to match the flexplate, it doesn't.
i left out 1 sentence
i bought the converter from a seller on craigslist
One hole is a dowel pin hole used on some 454's and the other 6 bolts aren't equally spaced-one is offset with a smaller angle and a larger angle-the others then have 4 equal spaces-with the dowel pin hole between a couple of them ------
its important for the torque converter to fit the recess in the crank EXACTLY as that is what centers it so it will turn the front pump smoothly-the mounting holes are ususally oblong a lttle to allow a little tolerance on the bolt circle however they should be equal at 120* angle
If the crank isn't balanced already then have it done with the flexplate AND a dowel pin in the rear plus an front dampner for internal balance--- if its already balanced without the dowel pin then don't use one