I have a 1990 Pontiac Firebird Forumla with the V8 5.0 305 TPI. It has about 130k on the stock engine now.


I am going to have to replace the stock intake manifold after a bolt snapped by the thermostat. Seeing as how I am going to end up buying a new Intake Manifold what else should I look at replacing and with what? Looking down into the valley it doesn't look like en engine has been ran extremely hard, with low oil, or anything else negative. I already have to replace the thermostat wire (damn thing melted on my headers a little bit ago), and the horn wire.

It already has Edelbrock headers with Max Flow pipes (dual exhaust) and I am dressing up the engine with a bit of color. I am also cleaning it up and making it look a lot nicer than it does now, but I want to get the most bang for my buck. I am not looking to increase my MPG (unless I somehow get extra HP with it too) but I also don't want a 4 MPG car either.

If the 3rd Gen members would be kind enough to impart on me the wisdom they have come across in their years with their car I would be EXTREMLY grateful!!!


J

 

I would think a timing chain would be good insurance for the future. If you are doing the chain, you could replace the cam with something like an LT1 cam or LT4 Hot cam. I have the LT1 cam in mine, and it really woke it up. Good time to replace the valve springs and seals too.

 

Hmmmmmmmmmmm decisions, decisions.



J

 

Why do you have to replace the whole intake manifold? Maybe you can drill it out. Is it one of your thermostat bolts? If you just take off your plenum you can probably just drill the bolt out. Anyhow, If you are going to take off the intake make sure you use a ton of RTV on the china walls. I would go ahead and replace the cam with a computer compatible cam. The LT1 cam's duration is just too close to stock,but is not bad if you are looking for a cost-effective option to adding more lift. (cheaper than adding 1.6 roller rockers) Maybe replace the o-ring for the distributor where it mounts to the manifold cause they are known to leak over time. Maybe adding an AFPR while you have the plenum off and the fuel lines disconnected.

 

.. X 2... Yes, best bang for the buck is simply drilling out the old bolt, put penetrating oil on it and see if an EasyOut can remove it, or HeliCoil it, or tap for next size bigger bolt...

.. Read the Super Rod TPI Intake comparison 'sticky' up above... also, the Performance Prom 'sticky'...

.. How much performance do you have now? Are you dissatisfied with it? How much performance do you want? Got a budget figure in mind? Can you swap cams, heads, intakes yourself?

.. The new GM #12370845 214/224 .488/.509" cam is great for a 305" with headers... stock cam was prolly about 207/209...

 

.

 

http://www.tpichips.com/305.htm

 

Always better to send one of your datalogs into a company like that. That way they can see what is really going on and what adjustments need to be made and then burn a chip accordingly.

 

http://www.tpichips.com/305.htm
This is the link to the recommended mods!

 

Don't you think that is a little too much cam for a tpi car. He is going to have to change out his springs too in order to use a cam with that much lift. Stock maximum lift is like .470/.470. A cam like that is going to give more power up higher in the rpm band anyway.

 

Sorry, I could have given a description. That site is really just a site for TBI chips, which you can ignore. The recommended mods page, however, is pretty helpful. Most of, not quite all, of what they post for the 305 rings true for our tpi cars, too.

 

I am not dissatisfied but with this being a northern car and with over 130k on it I want to make sure it gets all 'due or past due' repairs. I wouldn't object to an increase in top speed, acceleration, or even an extra MPG or 5.

I don't have any real set budget in mind, but its being done as I have time, and help.


I guess my main thing is if I need to replace anything to am going to consider it I want the best bang for my buck. I am not looking to replace the rear end, drive shaft or really the cam shaft as I haven't had to completely pull the engine as of yet. With any luck I can do everything without gutting my engine bay.


This all started so I could remove me headers and wrap them as the damn things were getting pretty damn hot.


J

 

.. Wrapping the headers may really shorten the life of them... if you can just arrange the wires so nothing gets melted, that's prolly all that's needed...

 

Why do you say that? I ask because I have seen many cars with wrapped headers with no issues.


This is my first muscle car I have actually worked on not just paid for already done (and it was a cheap meh car at that) so I am trying to learn alot as I go, just not to the tune of say a 5000 dollar repair bill.


J

 

.. Wrapped headers on occasionally used race cars keep heat energy inside the exhaust system for fast flow...

.. On a street car, wrapped headers contribute to daily heat fatigue and rusting out...

 

.. The GM 12370845 214/224 .488"/.509" hydraulic roller cam is the same duration as the often recommended for TPI Crane 2032, but with more lift for more low and mid RPM torque before the TPI RPM limitations set in, one of the 'secrets' of LSx engine performance...

 

Not trying to be a smart *** but where can I find this information besides your post?



J

 

Ok I need proper bolt sizes for a torx to regular bolt project. Too many damn torx breaking on me.


Anyone have a list?





J

 

The intake bolt thread is 3/8-16 I believe. An airfoil for the throttlebody and a set of SLP runners are easy improvements.Cutting the walls between the round holes in the plenum to match the SLP runners wouldn't hurt either.
I've had el cheapo headman shortys wrapped for about 5yrs with no rot yet.

 

Ok.............Good suggestions.


What about the rest? Seems like I had like 4 different sizes and styles of bolts.


J`

 

Not sure on the other thread sizes.I usually take my bolts to a local Napa store and have them matchm' up.
If you plan on using the stock runners, you may have problems if you try to use hex headed style bolts....Maybe not.
Another easy mod is to bypass the coolant hose running through the throttle body.There is a thread somewhere around here explaining the "how to's" on that topic.

 

No its not either. the 2032 cam is 214/220@.50 with 452/465 lift. and How is more lift for more torque a secret? Its like that for 5.0 Mustangs too.