My 377 build.

[INSIDIOUS '86]

what trans do you have?

[Reziel_1983]

Originally Posted by insidious '86

what trans do you have?

th 350

[INSIDIOUS '86]

the vacum modulator and governer control the shifts, do you want it to shift lower or higher? most poeple go with the corvette governer

[Reziel_1983]

I would think I would want it to shift higher... considering this motor would actually be better in higher rpms, but in all reality, I really am not 100% sure.

[INSIDIOUS '86]

well are you talking about wot shifting or just regular driving?
vacuum madulator controls in town and the governer controls wide open throttle

[BigBlocksRule]

It's not necessarily where it shifts, it's what the engine can do. Shorter stroke equates to slower piston speed and less ring friction. Slower piston speed means it will rev higher to get the same piston speed. It's not tough to build a bottom end that can take it, it's the valve train that really needs correct parts built right to get 'er done.

[Reziel_1983]

Originally Posted by INSIDIOUS '86

well are you talking about wot shifting or just regular driving?
vacuum madulator controls in town and the governer controls wide open throttle

I'm talking about WOT

[INSIDIOUS '86]

Originally Posted by Reziel_1983

I'm talking about WOT

ok well try out a corvette governer which shifts around 5600 i think and you should be happy with that

what kind of cam do you have? you want it to shift to a little after your powerband starts when it drops the rpm otherwise manual shift it

and dont forget a trans go shift kit to keep it alive under power

[Reziel_1983]

I have a comp cams xe268h. I believe the powerband is 1500-5800 rpm

[Reziel_1983]

If I manually shift it, is it going to hurt anything to shift it past 4k? Cause sometimes I'll manually shift it and shift it at around 4500 and it sounds like it's revving really high when I do that.

[Randy83]

We used to build a lot of 377's for our dirt racecars, if they are done right, they make great power in the upper rpm's... like 5000 and up, the only down side is that the 400 block is a little weak in the main webs for high rpm, if it has main girdles, they will live comfortably at 7500 or so. One of the machine shops we used built us one of these from a 350 block....bored it .125 over and it lasted a long time. I don't know how much heating issues it would cause on the street though.

[INSIDIOUS '86]

377's produce a unique sound unlike any other manual shift will not hurt anything and you will be fine spinning it to 5800, back in the day poeple would spin sbc and big blocks alike to 7g stock

5800 is a safe rpam that nearly any sbc should attain safely and isnt to hard on the engine

[Reziel_1983]

Originally Posted by INSIDIOUS '86

377's produce a unique sound unlike any other manual shift will not hurt anything and you will be fine spinning it to 5800, back in the day poeple would spin sbc and big blocks alike to 7g stock

5800 is a safe rpam that nearly any sbc should attain safely and isnt to hard on the engine

Cool, thanks for the info. I took it to 5k today but I still wasn't sure if it was alright to do so so I didn't take it any farther.

[slugish]

Originally Posted by Reziel_1983

Carb and timing is set.


1983 Chevy Truck with 377 stroker with xe268h cam - YouTube

Damn tose thumper cams sure do sound bad. Iwas about ready to get on e myself but a number of techs advised I would get better overall performance with a xe 274 which I ended up getting . Who knows , we,ll see once I get it in .

[Reziel_1983]

Originally Posted by slugish

Damn tose thumper cams sure do sound bad. Iwas about ready to get on e myself but a number of techs advised I would get better overall performance with a xe 274 which I ended up getting . Who knows , we,ll see once I get it in .

I don't have a thumpr, I have the xe 268. I might have gone with the thumpr but I read that they are all bark and no bite.

[slugish]

oh for some reason Ithought you said you had a thumper . Yea bark but no bite is what I have heard .

Ihave a xe 268 now & have boght the xe274
but my 268 sounds a lot tamer than yours ? maybe the exhaust

Ihave full lenghth headers > 3 in. collecter into one flowmaster , 3 in in & 2- 2.5 's out dumped behind rear wheel

[slugish]

oh for some reason Ithought you said you had a thumper . Yea bark but no bite is what I have heard .

Ihave a xe 268 now & have boght the xe274
but my 268 sounds a lot tamer than yours ? maybe the exhaust

Ihave full lenghth headers > 3 in. collecter into one flowmaster , 3 in in & 2- 2.5 's out dumped behind rear wheel. I WONDER if Ihad true duels would it sound better.

[INSIDIOUS '86]

have the small thumpr in my truck, alot of bite for a 420 hp 377

have to add 1.6 ratio rockers to the exhaust to make it more like a single pattern cam, really wakes up the cam, not to mention if you set the timing curve right,

im sure if i had some better flowing heads and intake i would be at about 500 hp and great streatability
bark with bit i tell you, the bigger cams for thier size do not deliver i admit, even then if your going to put a massive cam in why go thumpr?

[INSIDIOUS '86]

Originally Posted by Reziel_1983

Cool, thanks for the info. I took it to 5k today but I still wasn't sure if it was alright to do so so I didn't take it any farther.

its ok just got to build trust with you and your engine, im the same way with all my engines