engine kinda floats around redline

[adumb]

i have my th350 re-calibrated to shift at around 5,800 RPM. around 5,500 - 5,800 it kinda slows the rpm climb and hangs around a bit before shifting. i have a B&M shift kit in it. i don''t think its the trans shifting slow. i am kinda leaning towards my ignition not being able to fire fast enough up at those rpm's. any ideas guys? and if anyones agrees with ignition, whats the best solution or upgrades? thanks everyone!!

 

[85 Cutlass Brougham]

Sounds like valve float to me if it is not ignition related. What ignition do you have and what cam and springs do you have?

 

[Doober]

Yeah, stock ignition starts to struggle when you try to spin it up to 6k+... I'm thinking of switching to an aftermarket coil/module one day.

 

[85 Cutlass Brougham]

Supposedly, a stock HEI starts to have issues with saturation above 4500 RPM. My car has an MSD module and an Accel coil to help with this, but has problems with timing stability due to the old advance mechanism being a bit worn out. On my car, I plan on using the cheapest MSD HEI distributor to replace the 32 year old one that is in it now.

 

[Doober]

Oh, I thought it was a little higher :shock: Maybe I'll spring for a module at least.

 

[adumb]

i have a comps cam magnum 280h and the springs that came with the cam. ignition is just a regular hei coil.

 

[85 Cutlass Brougham]

Well, a stock HEI could be causing this issue, as could inadequate fuel volume to keep up with demand (stock pump?).

 

[adumb]

yes its a stock fuel pump.

so what would be the best upgrade for the ignition? as in cost equal to effectiveness.

 

[jrm81bu]

What heads are you running? If there stock that could be the problem, along with what the other guys are saying. My 400 has edelbrock heads, the cam that i used to have had 310 degrees adv. duration and 525 lift. Oh and the supercharger. It will rev as high as i want it to but power starts to fall off around 5500 and i shift by 6000.

 

[85 Cutlass Brougham]

For an ugrade, I would just buy the MSD HEI distributor you can get for (I think) $150 through Summit. By the time you buy a module, cap, rotor, advance curve kit for mechanical, an adjustable vacuum advance, and a high output coil for your old GM distributor, you could have had the MSD for cheaper. Now, this is not from personal experience just yet, but it is in my plans for the future as I need more initial timing and less total mechanical advance, and this setup was the cheapest and easiest way I found to get that and all new parts.