Red line for a stock 170/

[memike]

know that I am running my 390 Holley and dual 2'' to one 2 1/4 exhaust my little 170/ slant want's to jump over 5k rpm quickly.
Does any of our /6 gurus know where I should set my rpm red line at.
Specs = bone stock 1966 170 low deck / :happy10:
Thank you again for your thoughts on this, I just don't want to spin a bearing and hurt my daily driver :-D

 

[hellion_locdogg]

I would say 5.5k max... Some may say higher but I'd rather error on the side of caution. I plan on having my 225 at 5k because the cam stops making hp at 4.5 ish. Just another thing to consider.

,Cliff

 

[66aCUDA]

Mike
I dont think you can hurt it. 6K on a 170 is ok. I think you will run out of breath before then. Ask Charrlie S for sure as he is the resident 170 Guru.
Frank

 

[memike]

I would say 5.5k max... Some may say higher but I'd rather error on the side of caution. I plan on having my 225 at 5k because the cam stops making hp at 4.5 ish. Just another thing to consider.

,Cliff

Thank you Cliff, the 170/ I have is bone stock and is still pulling at 5k and feels like it want to keep pulling hard as it douse at 4k.
I think I will stay with 5k and be happy with that :-D

Mike
I dont think you can hurt it. 6K on a 170 is ok. I think you will run out of breath before then. Ask Charrlie S for sure as he is the resident 170 Guru.
Frank

It does seem to even out about 5.500, I just needed to know if I was over doing it. The little girl ran a 12.07 first and last pass at George Ray's 1/8 mile track and I did not hit her hard at the light, but I did get a good 0.37 light though. I am just 2 seconds behind some nice v8's running 10.00 so I am happy and will keep driving her until I change over to a new head you have for me and add a mild cam and new lifters :-D
Thank you Frank, She runs 2.500 rpm's at 55mph and my MPG is better with the new system :cheers:

 

[C130 Chief]

Mike,

If the engine is stock, I would guess 5500 is probably about right for you cam, and especially valvesprings. If you feel it peak at 5500, that's probably where it goes into valve float. Mopar used pretty light valvesprings on their low performance engines as sort of a rev limiter. The valves would float right past the point of peak power. This way the engine wouldn't want to rev high enough to hurt itself, making it somewhat idiot proof.

The best way to determine a reasonable redline (or in this case shift point) would be test and tune night at your local track. Make a couple passes shifting at 5000, a couple at 5500 etc... until it quits getting quicker.

If you plan a more aggressive cam down the road, I wouldn't change much until then. Just have fun with it as-is.

Also, go looking for a low gear set for your 904. Just about any mid 80's and later 904 variant (Dakota, Jeep) core transmission should have what you need. If you run 1/8 mile, this will be a big help.

 

[memike]

Mike,

If the engine is stock, I would guess 5500 is probably about right for you cam, and especially valvesprings. If you feel it peak at 5500, that's probably where it goes into valve float. Mopar used pretty light valvesprings on their low performance engines as sort of a rev limiter. The valves would float right past the point of peak power. This way the engine wouldn't want to rev high enough to hurt itself, making it somewhat idiot proof.

The best way to determine a reasonable redline (or in this case shift point) would be test and tune night at your local track. Make a couple passes shifting at 5000, a couple at 5500 etc... until it quits getting quicker.

If you plan a more aggressive cam down the road, I wouldn't change much until then. Just have fun with it as-is.

Also, go looking for a low gear set for your 904. Just about any mid 80's and later 904 variant (Dakota, Jeep) core transmission should have what you need. If you run 1/8 mile, this will be a big help.

Thank you Chief :happy10: I really don't want to do much racing with her, she is a happy little driver that I will get back to as close to mint as I can, I have the original 3 speed standard trans three on the tree.
I enjoy driving her every day and looking forward to a better flowing head and just a good RV cam. Trust me Chief :happy10: I am enjoying driving here to the store and a few road trips :happy10:
I took it to a car show not long ago and got it inspected and scored a perfect 23