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-   -   400 sbc powerglide trans top speed 1/4 trap (http://www.hotrodders.com/forum/400-sbc-powerglide-trans-top-speed-1-4-trap-228697.html)

savage9scorpio 01-22-2013 07:09 AM

400 sbc powerglide trans top speed 1/4 trap
 
okay I have a 400 sbc stock bottom end. aluminum dual plane intake, 750 qjet, stock heads (for now) and a powerglide w/2.73's AND 488/510 CAM WITH 114 LSA. I haven't got the timing done completely so its still a lil off and I've been advised not 2 go WOT until I do get the timing down. but so far I love the 400's torque compared 2 the putt putt 307 I had.

the motor shifts into second around 40mph. can drop down 2 20mph while its in 2nd.
BUT MY QUESTION IS WITH A WIDE LSA WOULD THE TOP END BE MORE THAN a smaller lsa cam?
when I'm in it it feels good on the highway I'm cruising @ 72 right around 1900 rpm. this is a STREET CAR. I haven't gotten into the throttle 2 much but what should be top end speed when I do get into those big secondaries?

vinniekq2 01-22-2013 07:15 AM

google gear speed calculator
Gear Ratio Speed Calculator
this will tell you the speeds in gears.
why are you not using the secondaries?

5500 rpm will generate around 90 mph plus or minus,depending on tire height

cobalt327 01-22-2013 08:36 AM

Quote:

Originally Posted by savage9scorpio (Post 1637538)
okay I have a 400 sbc stock bottom end. aluminum dual plane intake, 750 qjet, stock heads (for now) and a powerglide w/2.73's AND 488/510 CAM WITH 114 LSA. I haven't got the timing done completely so its still a lil off and I've been advised not 2 go WOT until I do get the timing down. but so far I love the 400's torque compared 2 the putt putt 307 I had.

the motor shifts into second around 40mph. can drop down 2 20mph while its in 2nd.
BUT MY QUESTION IS WITH A WIDE LSA WOULD THE TOP END BE MORE THAN a smaller lsa cam?

A wider LSA favors top end over bottom end, but the difference won't be huge unless the cam is a mismatch from the get-go. An article that compares various LSA in a SBC 400 (as well as open and divided plenum intakes): http://www.chevyhiperformance.com/te...t/viewall.html

Also, many cams have ground in advance when installed at the recommended ICL. This doesn't change the LSA, but tends to bolster the bottom end.

Quote:

when I'm in it it feels good on the highway I'm cruising @ 72 right around 1900 rpm. this is a STREET CAR. I haven't gotten into the throttle 2 much but what should be top end speed when I do get into those big secondaries?
Wallace Racing - Automotive Calculators

savage9scorpio 01-23-2013 08:39 PM

aye cobalt327, good looks on the article but then another question after all the tests comes into mind. Does a hyd flat tappet respond to the same lsa feats of the hyd roller.
I would think on alot of lines they should resemble one another but I guess Friday night test and tunes and my weekly pays checks will help me figure tht out.

I had got the cam I used for pretty cheap ($30) and wanted to see how it sounded and felt since I had it. here ill let you all here it 2.

.

I can only hope I don't get any complaints from my neighbors when I crank it up 4 work in the am :spank:

techinspector1 01-23-2013 08:53 PM

Quote:

Originally Posted by savage9scorpio (Post 1637538)
what should be top end speed when I do get into those big secondaries?

Hell boy, she ought to be indicatin' about 317 if you can wind her up tight enough. Pedal to the metal. :eek:
About 10,400 on the tach with a 28 inch tire ought to do it.

cobalt327 01-23-2013 08:55 PM

Sounds good.:cool:

The LSA behaves the same regardless of what kind of cam it is. If the cam you have now was a 108 LSA it would be rattling the fenders- lots more lope to it. That cam you have would be more radical sounding if it was in a 350 engine instead of the 400. But overall, I like the sound of it.

I'd route the pipes out the back or side, though. Having them end under the car you might get a drone inside the car and the chance of carbon monoxide getting in the cabin is worse.

savage9scorpio 01-23-2013 08:57 PM

Quote:

Originally Posted by techinspector1 (Post 1638146)
Hell boy, she ought to be indicatin' about 317 if you can wind her up tight enough. Pedal to the metal. :eek:

317 what?? cars passed per hour?? lls

savage9scorpio 01-23-2013 09:01 PM

Quote:

Originally Posted by cobalt327 (Post 1638148)
Sounds good.:cool:


I'd route the pipes out the back or side, though. Having them end under the car you might get a drone inside the car and the chance of carbon monoxide getting in the cabin is worse.

Thanks!!. . . and yeah I'm hip 2 the drone sound especially from the one thts up under my feet. I hear it @ a certain rpm range. Ima get the pipes routed this week. don't wanna look over n see my girl passed out from the fumes type shidd.

and looks like I'm about to start searching for another cam ASAP.
I've always had a thing 4 LUNATI. but cam selection is a headache

vinniekq2 01-23-2013 09:25 PM

Not sure about the turn downs also being a lot smaller diameter? small tube headers,nice little cam,should be fun to drive for now. The extra 100 cubes will help also

vinniekq2 01-23-2013 09:37 PM

rofl,Tech,did you use the speed calculator? 187 in low?

techinspector1 01-23-2013 09:42 PM

Quote:

Originally Posted by savage9scorpio (Post 1638156)
I've always had a thing 4 LUNATI. but cam selection is a headache

Not really, call and talk to one of the techs.....
contactlunati_aspx ::

techinspector1 01-23-2013 09:45 PM

Quote:

Originally Posted by vinniekq2 (Post 1638176)
rofl,Tech,did you use the speed calculator? 187 in low?

No, I just used the formula out of my head....
revs divided by gear times tire CIRCUMFERENCE divided by 1056.....Just having some fun Vinnie.....:thumbup:

vinniekq2 01-23-2013 09:54 PM

I couldnt do that formula in my head,lol.I use the calculator
Glad you are back and having fun,,,


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