91ChevyRS

Well, I sort of like maybe 80 percent fixed my misfire problem in my car yesterday. I decided to take her out for a spin soon afterwards.

I dropped it down to first, and just punched it from then on, I uhh...well I forgot to shift at the right moment so I accidentally took the car to 6000 rpms by mistake (i'll never do that again, )

I was just thinking that, I took the car that high in the RPM range shouldn't it have bounced off a rev limiter or something? Do the TBIs not have one?

And if not, isn't that like...not good?

Fast355

iTrader: (2)

It has a speed limiter, NO rev limiter though. Its not a big problem IMO.

91ChevyRS

I am surprised it actually held up that far, whenever I manually shift I usually shift into gear at like 5000 rpm sometimes 5500

Fast355

iTrader: (2)

The stock tach is not accurate at all. I would be suprised if you peaked 5,000. Especially if you have the original 100,000+ mile valvesprings on there . They will barely make 5,000 rpm when they are new and have the proper spring pressure. 6,000 is in my experience is not possible without major spring upgrades.

91ChevyRS

wait so, your saying that going 6k in a relatively stock LO3 isnt healthy.

Oops....i hope that doesnt cost me in the long run

Fast355

iTrader: (2)

It typically won't hurt the short-block, but the valve springs will float before you can do any real damage to the short block. Too much valve float is a bad thing.

91ChevyRS

I dont neccessarily want my car to be a high revving powerhouse, but what are some of the things I can do to make it....stronger in the upper RPM range.

My valve seals are bad, but I plan on waiting until I have enough money for new heads anyway..although I really dont know what heads I should be looking at for a car like mine.

matt_p

Well, you stock engine isnt making you any power after 5000 rpms, so there is no point in going higher. But if you do want to be able to go higher later on. Stiffer valve springs is what you need. Full roll rockers help in the upper rpm range as well. Less friction.

Casey Butt

The stock L03 is extremely limited by the exhaust and the intake "tube" that it has to breath through. Those exhaust manifolds limit power throughout almost the entire RPM range. Past 4000 RPM or so, and the engine is simply choked. Your first and highest priority on an L03 should be a full exhaust (headers, cat-back, etc). That alone will give you 30 hp (more with an open element breather) and probably 1000 more useful RPM. Plus, it will allow the engine to make use of any future modifications also.

It isn't desirable to have a "street" 305 spin more than 6000 RPM. For that you need stock 1.84/1.5 valves or 1.94/1.5 valves (but this might create shrouding problems). Also, your stock heads (especially ported) will support 275 (at least that's what people on here say - and similations verify it). If you get some 305 heads from the TPI or carbed 305s you can make 300 hp (with the right cam of course). If you port those heads good you could make 350+ hp.

A 305 doesn't need super-flowing aluminum heads ...at least not if it'll be making its power under 6000 RPM. The extra flow of such heads is unnecessary because the 305 simply does not demand it in order to fill its cylinders (below 6000 RPM). Plus, aftermarket heads to fit the 305 will have larger intake runners and bigger intake valves - both of these may actually limit performance in the RPM range that you want a street car to perform. So, in the end, ported stock 305 heads will flow all you'll ever need for a 305 that makes its power under 6000 RPM. ...People complain that there aren't many good aftermarket heads for the 305, but the fact is that the 305 doesn't need aftermarket heads for what 99.9% of owners want the car to do. Luckily, the stock castings have the potential to be modified for that.

91ChevyRS

well i hope everything goes fine with the car....it was my mistake, not really something i'd do again.

How do you know if you have too much valve float?

3rdgen92maro

i doubt any damage was done. i used to take my L03 deep into the 6000rpm range. i owned it for 2 years and beat the hell out of it without any engine problems due to over revving.