Currently rebuilding a stock c4 engine and I'm wondering while I got it broken apart what kind of parts need upgrading and what are some good performance mods.

 

I'm not going to be of help on your question, but if I can make a suggestion? It would be helpful to know the year, type engine and transmission as they do have a bearing on what works and what doesn't.
Also what you're trying to get out of it along with expected usage.

Good luck.

 

Just want a little extra power and I want some better parts that at gonna last longer it's a 350, 91 c4 stock trans

 

A stock engine should cruise right on by 300,000 miles with proper maintenance...how long do you want it to last? I'd doubt you'll find parts that last longer than stock parts.

X2 on "goals and budget". "Just want a little extra power" is a bit vague, but going off that, I'd throw a cam and headers at it, then add a proper dual exhaust when you put it back together.

 

What you want out of the car along with the budget should be the deciding factors. If I was going to rebuild my '91 I would put a cam in it new valves springs retainers nd keys with a good 3 or 5 angle valve job+ pocket porting. Intake and headers can be added easily with the engine in the car. The same for exhaust system. Obviously change all belts and hoses as well. Not a bad time for a new stock damper and do make index marks on it so you can check for slip/spin of the outer hub down the road.

 

OK - Engine basics 101.... Think of an engine as an air pump - the more air (and corresponding fuel) you move through the engine - the more power you make.

So - most experienced engine builders will tell you that the key to making power is to make air flow. A good set of cylinder heads and intake / exhaust systems that don't restrict flow - and you'll make power. More displacement (cubic inches) = more airflow = more power.

Cranks / rods / blocks don't make power - but they have to be robust enough to stand up to the power that you're making. A bone stock 2 bolt main block will be more than adequate for a 180 HP Throttle Body injected engine that never sees over 5,000 RPM. That same block will break in half if you spin it to 8,000 RPM, and try to push 700 HP to the trans input shaft.

So ... what are your goals here ??? The reason the other posters are asking is that without having an idea about where you are now and where you're trying to get to - there is no way to give you decent advice. If you're looking for a 5% - 10% increase - a decent set of long tube headers and a low restriction exhaust (and possibly a PCM reprogram) will probably get you somewhere in the ballpark - but experience has shown the L98's and LT1's are different animals, and respond differently to certain types of mods.....

 

It's a tuned port so the intake will be the limiting factor.That being said air in/air out.You have to be able to tune afterwards and that is a challenge by itself these days for most people.

 

Get your intake and plenum ported, and a LT4 hot cam, and headers (+ tune). That will wake the L98 up, and you will love it!!! You should get Plus/Minus 50 hp, and a muscle car sound without breaking the bank. a stall converter will help if you have an automatic.

If you go further down the rabbit hole... it will be endless....