Grumbles

So I'm new here, been surfing the forums for a couple days and decided to register as the forum as a whole seems very knowlegeable and helpful.

I have a few questions regarding my 1988 Pontiac Firebird (formula) and it's tired old 305. Just so the details are available, I own a 1988 Pontiac Firebird with a TBI 305 and a 5-speed manual behind it.

I just purchased this car from a gentleman who claims the motor has never been rebuilt. True or not, it's seen 175k miles and blows a good deal of smoke, and there's no doubt in my mind that the heads are toast and the rings are probably worse. Chances are the cylinder taper is pretty rough as well, so if it gets rebuilt it will need to be machined (no ghetto garage honing for me ).

My questions are as follows. I'm looking for a quick, painless way to get her running acceptably again. My two options so far are 1) Rebuilding the 305 or 2) Throwing a 350 in it. Rebuilding the 305 would be simpler (already have the motor, TBI wouldn't need to be junked, proficient in that sort of thing) but it's fraught with potential problems. Crank could be a mess, cylinders might be .60 over...etc etc.

Being a recent Ford convert and a novice mechanic, there's quite a bit about the 350 swap I don't yet understand. The engine in it now is TBI. Will the computer be able to handle the extra 50 cubes or am I better off carbing it? TPI is a hassle to wire and I'm terrible with electronics, so that's out. Thankfully it is a stick shift, so if carbing is the only answer, it wont be too difficult. If I swap the 350 in and it's from an auto, will I need to use my 305's flywheel? How can I be sure that it will be balanced correctly (or close enough to not matter)?

What sort of 350 should I be looking for? Roller or flat tappet, neither matter to me, and I'm not looking to make a monster out of it so 2-bolt main is fine. What I'm really hunting for is compatibility. Cheap and uncomplicated has always been what I've liked about GM, and it's what I'm looking for now.

Do any of you gentlemen think I'd still be better off keeping the 305? I understand with better heads and a half decent exhaust you can actually get some decent numbers out of them.

Any answers or helpful tips would be much appreciated. I've always been a GM man at heart, I'd like to finally have a vehicle I can stick with and not end up frustrated.

Rolling Thunder

For starters welcome to the site im sure youll find the other members here more than helpful on whatever you decide to do. No as for rebuilding the 305 or replacing it to the 350 there are several things to consider.

1 expense
The cost of a rebuild is determined by the parts to be replaced/ machine work. At 175k i virtually guarety youll need to punch the cylinders but even at that by their nature rebuilds designed to be cheaper than replacement. Cranks can be reground cylinders can have sleeves installed machinists can work magic and fix just about anything economically lol. Buying a new more popular 350 on the other hand might be comparable as far as cost is concerned at about 1600 for a non-roller block.

2 Reliability
Although chevy v8s have a long history of reliability the t-5 has proven itself unreliable lol. although ok behind stock 80s emissions choked 305s even thoes pushed the t-5 to its very limit. I think there rated for 275 tq when even the low performance lg4 305 put out like 250 or so. For a few years you couldnt even get the t-5 behind the 305 tpi till they upgraded to the world class version and never was an option behind the 350. So what im tring to say is a healthy 350 will turn the t-5 into a paper weight eventually unless driven nicely and lets face it who dosnt get on it from time to time?

3. Legality and emmissions
Swapping to a carbed 350 will not be technically legal. You might still be able to get it to pass the sniffer but technically still illegal.

4. The swap itself
Swapping to a 350 and maintaing the tbi is possable its been done before i cant personally give any good details on it but which is cheaper keeping the TBI intake and making the neccessary adjustments or going carbed? Going carbed would be easier but it might be cheaper to stay TBI. Though again mods will be needed as im fairly certain the factory ECM wont be able to compensate for the additional 50 ci. Other than that the 305 flywheel will work ect as the 350 and the 305 are the same motor minus the cylinder bore.

Long story short rebuilding the 305 would be the easiest thing most likely cheapest as nothing needs to be modified but that depends on whats needed obviously. However swapping to a 350 has a strong argument for performance and the cost of the rebuild vs a new non roller 350 would be pretty similar and then you have bran new motor not just rebuilt. So really at the end of the day its a judgment call.

stroker_SS

What are your plans with the car, if going fast is of concern now may be the time to swap in a 350 or bigger. If you just want something to drive just have your 305 rebuilt to stock specs(well a bigger cam won't hurt much).

Grumbles

thanks both of you for replies, rolling thunder yours is definitely food for thought. Can a TBI setup take a bigger cam? Wont that goof with the ecu?

Rolling Thunder

Well that would be a question for the TBI section of this forum. All fuel injection systems are just based on sensor inputs so all systems to some degree will be somewhat tolerant to changes. Some are better than others but the real question would have to be is how big of a cam are we talking about? Once you know what cam your thinking of useing then i would ask in the TBI section to see if others have had luck with a cam of that size running on the factory program. Worst case scnario you can have the chip reprogrammed just send it out with the details of your build thell program the chip send it back to you.

Grumbles

Not looking for some gasping behemoth cam to take my tired 134hp dyno'd smoking block up in the 300's, just a little bit more oomph. I need to do some research on factory cam lift and duration before I can make an in-depth decision.

Rolling Thunder

Well to get up into the 300s on a 305 will take a decent set up not only cam but probably everything else too. TBI motors werent exactly the best performance set up. At that rate u will need a tune.

aciddrop2804

well you didnt mention this as an option, but a good running used 305 can be had for a mere few hundred dollars on craigslist or other places. that could get you through until youve had the time to build up a proper 350, or even a whole lt1/t56 setup can usually be found for about 2000 which is what i would like to get when i have the funds. just something to think about. happy wreching!

Grumbles

The trouble with the 350 concept is that until I'm 25 the car cannot be registered as a collector and wont pass emissions. being only 21 now, that's still a ways off.

Right now, I think the best thing would be to attempt to get the 305 in good shape and just continue lying to myself that I'm doing so to keep the car "numbers matching" (lol).

After doing a bunch of sticky reading however, I find myself feeling a bit frustrated. Heads that are worth anything are almost completely non-existent for the 305 in the below $500 range. I could port and polish the existing heads, but from what I've read they are of the "Swirl" design, one of the worst concepts in automotive history.

Can 76CC heads be milled all the way down to 58-60CC? Probably not huh, lol. Can I grind the "swirl" ramps out of the current heads and turn them into decent breathers? I haven't been able to find a definitive answer to this question yet.

Even if I put some good heads together or giant CC heads can infact be milled down...I'll still have to burn a new prom, which will take some pretty significant learning, and I'm the first to admit I'm mentally challenged when it comes to electronics. Sigh, so many questions. I get one answered and 3 more pop up.

Rolling Thunder

Well yea heads for less than 500 that would be a challenge. Emissions is kinda a tough one because even though a 350 is larger if you read the emmissions report its all in PPM or % not the actual volume of emissions so the 350 or 305 should have a roughly equal chance of passing equipped equally. However technically it will fail as its not a legal swap to go carbed and to go 350 you would be forced to use a TPI 350 a LT1 or an LS1 swap and retain all the emissions. Now on to your motor yes thats what i mean about the TBI motor everything about it just sucks from the factory no offense to TBI motors. Now the question is what can be done about it? The cams in all our 305s sucked so an aftermarket cam of some sort would help greatly and many are available that are emissions legal. heads vortec heads are great and cheap around 600 for a pair new. Now as result youll have to work something out with the EGR valve and a new intake to match the vortec heads but there's into on that around on this site already so i wont get into that. Other options are the corvette l98 heads and even the factory 305 tpi heads would be an improvement. Your heads cannot be milled down that far and even if you could you would have to really mill down the intake as well. However the intake set up there's not much you can really do if you want to remain TBI edelbrock makes intakes (street legal ones) but the design of TBI is just simply not the best. Its a nice cheap reliable set up but its not really a performance oriented design. Now as far as the chip burning is concerned there are many companies out there that do this for you. You just send them the specs and mail them the ECM or chip and they send it back to you reprogrammed and your on your way. However even after all this if you wanted to remain street legal and used the TBI intake ide guess you would be a mid 200 number accounting for a 25% loss in the trans a high 100 at the wheels.

Grumbles

wont vortec heads mean i have to ditch the TBI system altogether? I'm trying to keep it reasonably close to factory, for ease of installation and cost purposes.

All in all I'm willing to drop around 5-6 on heads, and I'll be buying a set of non-legal headers and tapping A.I.R. holes to keep them legal. I'm REALLY trying to get away from the swirl style heads, as everything i have read on this site says they are terrible...I'm having a hard time locating anything that I can just swap in though (L98 heads on ebay are scarce, need the TPI head code to even look for them at all)

I know I'm probably asking a bunch of questions that have been asked before, but I'm not very internet savvy and finding the right key words to get the info i need around here is proving difficult.

If anybody has a set of TPI or L98 heads lying around, let me know, we'll work a deal out. Otherwise, does anybody have the code for them so I can look them up? And why the hell is edelbrock's website so un-user friendly lol

Rolling Thunder

well going to vortec heads does mean you need a new intake to match but there are aftermarket TBI intakes for vortec heads (or a factory TBI intake for vortec heads). For head casting numbers i believe 083 is for the camaro firebird l98 350 tpi heads (cast iron), 113 is the corvette l98 heads (aluminum), 081 is the 305 TPI from 87-92 (cast iron), and i dont recall what the earlier 85-86 305 TPI heads were maybe some can chime in on that one.

Grumbles

Sounds like I need to get it past emissions then just gut the top end and toss on a pair of vortecs and a carb mani. They make vortec carb mani's, right? :P

Rolling Thunder

Yea they make vortec carbed intakes. As far as emmissions go make sure your truely dont with them befor going through with it even though you can get just about anything to pass the sniffer (you should see some of the miricals i pulled off with emissions tests lol) If the go looking for a visual inspection you could fail that. Also if your going to throw emissions out the window it may be time for a 350 swap as well as its not really any different that putting in a 305 but will probably be cheaper give better performance and more likely better gas mileage at that performance level. Remember what i mentioned about the transmission though.