307 Olds H/O stiffer valve springs necessary?

[DoubleV]

Your idea of a freight train differs from most I guess, but if you think you'll be happy then that's all that matters. The thing is, after you get used to the new level of power, you're gonna want more.

I actually drove a 1993 Cadillac Fleetwood for a couple years previously before I got the Regal. It was supposedly rated at 180HP and 300ft.lb. That is what I want my car to be like. That car had more than enough power in all situations. I don't know what gears are in it, but they only came with either a 2.93 or 3.08 (I am leaning more towards 2.93 as it is a non-tow package). Power really isn't a big interest to me, I am more concerned with having a smooth running and more reliable car.

Compairing HP numbers straight up can be very misleading because they never tell the whole story. There is the torque curve of the engine to consider too. It was probably a pretty spunky car within it's RPM range because of it's good torque, but the VIN 9 roller has a much narrower RPM range where the engine really pulls and has much lower torque to begine with too.

Also the better gearing of the Caddy ( steeper transmission gears too ) had alot to do with it's performance as well.

If you want your roller 307 ( with VIN 9 cam and only 2.56 gears ) to be anywhere near what the Caddy was, you're going to have to do a bit more work. Raise the CR and get a good valve job at the least. You'll probably need headers too and of course a very good tune. With your mild gears, it's still not gonna have any get up and go off the line, but should run OK on the highway since your goals are mild.

 

[Mike P]

If you’re not going to be winding the crap out of it chances are the non-performance springs will do fine.

One thing you could do is have your machinist look up the open and close spring pressure of the HO springs and compare them to the actual spring pressure of the new Non HO springs. It may be as simple as shimming the non-HO springs for slightly more pressure if you want to go that route. He may even be able to cross reference another spring that will work.

Just a thought.