1991Formula350

Man, I wanted to sell my 350 for so long and now a few months after it is gone I miss that damn car. I kept my 305 because it still look's new and has low mileage, but damn does this sucker suck, no damn power!!!

I am looking to see what I can do to boost the power in her, it has no punch and see why 350's are so much in demand! Andy

PETE

iTrader: (1)

nitrous is a good equalizer!

Beyond that you have the more expensive power adders...

86Z

iTrader: (4)

i have no problems with my 305

ZONES89RS

iTrader: (2)

No matter what you do, until you put some internal mods it will be slower than the 350, you will need to cam it up, all bolt ons will get you close.

Mudweiser_Matt

if you have a 5-speed and know how to use it they'll hang with a 350. i raced a ls1 formula and jumped on him from take-off, but he got me after second gear.

Randy82WS7

its all about the axle ratio

any engine is a slug with 2.73

what ratio you running

if its not at least 3.42 then go to a yard and get one

and right now

you will be glad

good luck

j0n

iTrader: (1)

my p600b procharged 305 put down 390rwhp

browncamaroz28

iTrader: (1)

i disagree totally, you can boost it and leave most n/a 350's in your dust...

1991Formula350

What type of shop does rear axle or gear change for this type of car? I am not a mechanic, and how many hours of labor should it be so when I look around I am not ripped off like they tried to tell me on my heater core needing 6 hours of labor (which I refused and had bypassed). Please, all replies are graetly appreciated. Thank you! Andy

186irocz

My stock 305 with just a magnaflow ran 14's, some monster engine eh? This year its remaining stock, but next year im gettin a serp setup a procharger and some killer internals.

freestylzz

Having the 350 is alot nicer

Sorry to hear you let it go. Too bad you didn't swap it.

Mudweiser_Matt

YOU 350 GUY'S DO KNOW THAT THE ONLY DIFF BETWEEN A 350 AND A 305 IS THE BORE. THE CRANK, ROD'S AND STOKE ARE THE SAME. I READ THAT THE ONLY THINGS THAT MAKE THEM LESS POWERFUL ARE BAD HEADS AND CAM. ONCE YOU CHANGE THEM OUT THEY'LL STOMP A STOCK 350!

Stephen

iTrader: (12)

It's not like you can simply bore a 305 and BAM! you have a 350. Even .030 over bored, and a 400 crank, your still only looking at 334 cubes.

If you think a simple cam and head swap is gonna stomp a 350, your only partially right. A cammed and headed 334, might take a stock 350. Throw a few mods at a 350 (without even touching the heads and cam, and the 334 is behind again.

Don't get me wrong, I have nothing against 305s. But in the end, the 305 is just a step above the 307s. Good for basic transportation, but not real performance.

Mudweiser_Matt

WELL, SAY WHAT YOU WANT BUT I THINK THAT HAVING A SMALLER DISPLACEMENT ENGINE RUNNING JUST AS FAST OR FASTER THAN IT'S BIGGER BROTHERS IS FUN AND DIFFERENT THAN HAVING THE SAME SETUP AS THE NEXT GUY......BUT THAT'S JUST ME!

Stephen

iTrader: (12)

FYI, typing in all caps, is seen as yelling.

You want smaller cubes? Go 327. They make good power, and rev to the moon, so they are great for a road course/autocross.

Mudweiser_Matt

MY BAD ABOUT THE CAP'S, THIS IS HOW I TYPE FOR WORK (DRAFTING). 327 OR EVEN A 302 WOULD BE SWEET. NOT MANY 3RD GEN'S WITH THOSE POWER PLANTS, YOU CANT BET ON THAT!

Stephen

iTrader: (12)

I'd suggest turning your caps locks off on posting...it's 1 simple key stroke. Back on or drafting. It's just being polite, and not being seen as rude or aggressive, IMHO. Just a suggestion.

A 327 would be sweet. I have a magazine test, where they took a 327, dyno'd it stock at 192hp, did a Vortec head and a Comp Cam cam, for a total of 345 hp! They even used the same carb, headers, and dizzy on both tests. So, you are looking at what? $600, for a 153ho gain? Not bad!

Jeremy Z28

iTrader: (5)

The 305 vs. 350 argument will never end. Both have potential, it's just that the 350 can net more HP for cheaper. The 305 just takes more cash to get there.

Some advice to the original poster, if the engine is low mileage in good condition, and the rest of the car is worth it, you can always go the supercharged route. Decently expensive, but you're working with what's already there, and will be much quicker than a stock 5.7L. Look at 86Z's sig above

8T9 BANDIT

i ran a iroc with a carbed bored chevy 327, it looked like a show car it was beautifull all chromed out etc,, i whipped him by about 2 cars in my stock 89 305 with a chip, k+n, and an airfoil..

1991Formula350

But has anyone taken there car to a shop to have the gear changed? Yes mine is stock, 40, 200 as of today sadly, I try to keep mileage off, but I need to drive. I have the 2:73 I need to find out about that. Thanks! Andy

Stephen

iTrader: (12)

Are you referring to your speedometer? This thread has nothing to do with speedometers.

You hafta change out the little gears in the tranny end of the speedometer cable, to getyour speedometer to read right, after changing out the rear gears.

1991Formula350

No, the gear. I want to change it, but has anybody gone to a shop to have it done? How long does it take, etc. Thanks! ANdy

Stephen

iTrader: (12)

What gear? Rear end? Speedometer cable has 2. Which gear? A little more specific please.

I'm not seeing how any gear has anything to do with a 305 to 350 swap.

Xophertony

Stephen - this thread is not about an engine swap, it is about making this guys 305 faster. i know usualy making a 305 faster means a 350 swap, but not always

1991Formula350 - yes, you can have shops do gear changes, however this will be costly. a better, cheaper alternative would be to hit a salvage yard, craigslist, or TGO's for sale boards and buy a whole new (used) rearend, complete from drum to drum. then swap it onto your car. this is better for two reasons.
1. this takes WAY less time.
2. you now have a spare rear end should your new proformance one blow up.

a rear end swap will take somone who is experianced verry little time. like and hour or three. if you have never done one before plan on spending 2-5 hours on it. if nothing else just because looking up tourque specs takes so damn long. i have done one rear end swap on a thirdgen, and dropped the rearend a few times for fuel pumps. it does not take me long. i'll list off the steps to illustrate just how little there realy is to do.
-undo the 4 bolts and disconnect driveline and leave it in the tranny, otherwise you will need to refill your tranny. use a screwdriver to hold the driveline still so it does not rotate.
-disconnect shocks
-disconnect lower track bar @ rearend
-disconnect sway bar
-disconnect tourqe arm
-disconnect rear control arms @ rearend
-disconnect brake line @ body
-lower rear end and lift springs out (they will be totaly free)


installation is the reverse of removal

RE 350/327 - i raced a fellow board members 1987 formula. it had a Carbed 327 with a well built 700r4. i was in my 88 Trans Am GTA with an L98 and a WC-T5 (and before you start I put the T5 in, and the block is casting numbers confirmed 350)

I only beat him by a tenth or two.

Mudweiser_Matt

1991formula350,
a couple years back i had gears put in my 4th gen. i took them a few day's and me $1400. but they "said" they neede to replace my eaton diff unit, which was about $600 to $800 itself. so i would assume it would cost about $800 plus the price of the gears. but you can ask anyone, it's worth getting lower gears when it comes to racing and stop light racing. but save up some money for gas!

chris86sc

Yeah I had 3:73 gears installed in my SC, let me tell you with the headers, 3" H.O. Exhaust , MSD, K&N and Dual Snorkle Air Cleaner this thing is like a complete differant car. The posi install also cost me about $800 too.

Like Matt Said "Stop light racing" I do pretty good with this setup.

1991Formula350

Thanks guys, yes that is what I was talking about. I am in Miami, Florida. I will call trans am creations as they are close to me and see what they quote, I wish I was closer to Hawks for them to do it as they have excellent service! I do not want to switch engines also, like stated above.
I will print this thread and get back the day I get it done. Thanks again everyone. Andy

jaysfs

iTrader: (1)

you guys got ripped on gears. I spent $189 on richmonds 3.73. And 100 for the master kit. Then I know a mechanic at a gm dealer and he gave me a great deal. He installed my gears put all new seals and u joints on my driveshaft for$ 220. He did a awesome job as well. Look around before you have your gears put in

rik89gta

It ran me about 800 in labor and parts to have 3.73 gears installed in my 98 Z28. The car ran completely quicker, and it reved up soo much faster than it did with the 2.73's. They were having a hard time shimming the ring and pinion so that probably drove up labor costs a bit. I believe the shop was called Trans Pros located in Lombard Il. I don't think they were too professional though because my pinion seal started leaking badly after just a couple months.

89_ho_rs

when I put the 3.73's in my car(i had the 2.73 gears originally) it was like putting in another motor in my car on top of the 350 i had in it originally. 1 and 2 gears pull so hard. the car is soo much fun, I never thought a gear swap would have had that much change on it.

Mudweiser_Matt

YEP! They sure are worth the money and hassle.

327_TPI_77_Maro

iTrader: (8)

Having a cubic inch disadvantage is really not all that glamorous. Maybe someone might be impressed? I won't be. Given the choice take the cubes.

89_ho_rs

I have always hear the phrase there is no replacement for displacement. but then I actually heard that the difference betwween a 327 and a 350 is the difference between a race horse and a work horse.

327_TPI_77_Maro

iTrader: (8)

I run a 327 currently but it is being replaced with an L98 based 383 in the next few weeks. A 327 just doesn't make the power a 350 does at the same state of build. Sure it revs high but it makes less power at a given rpm than a 350 would given the exact same parts. Onwards and upwards.

D's89IROCZ

You will find the change of gears , will give you the biggest seat of the pants feal . Like from your 2.73 to a 3.73 .... it's gonna haul ****. I payed $250 for gears and , 250 for install. $500 should be a fair price .

Mudweiser_Matt

So that would make a 305 an JACKASS! Slow but faithful!

8T9 BANDIT

this 305 debate is getting retarted, a fast f-body is a fast f-body. ive seen naturallt aspirated 305's run 12's. i have also seen supercharged and turbo 305's even hit the 11 mark..very fast?? 350's are great too of course, cam and heads and youre runnning 13's with some bolt ons, stroke one out and sky's the limit. both these sbc are great motors. neither one sucks! but i will tell u a 4 cylinder honda sux!. so lets kill this stupid debate, make our small blocks all haul ***. and bury the rice burners..

Mudweiser_Matt

Well I didn't think it was a debate, I thought it was discussion. I think that everyone would agree that ANY GM motor, big or small are the best. But I don't know why some think that the 350 is the best there is. Yes it is the most common and cheapest. But as for displacement wouldn't you say a 400 is king and for rev's a 302 would be prince. So the discussion was about why 305 aren't just paper weight's.

8T9 BANDIT

i was refering to the debate that comes up everytime a difference in our motors comes up anywere on this forum. i never hear blue oval guys arguing about 302's and 351's .

Mudweiser_Matt

I never hear them either, cuz there usually crying from the *** beating they just received!

8T9 BANDIT

thats a nice t/a mudweiser, have any more pics?

Mudweiser_Matt

Thanks! No, I don't. It's almost completly stock so i really don't have anything to show off. I have a whole box of crap from summit (headers, msd, injectors, etc...). I plan on putting it on next weekend. I'm spending alot on money on that car just fixing ware and tear parts (shocks, motor mounts, 2 tranny mounts, sway bar endlinks) that I haven't really modified it YET!

Damon

Back to the original question for a minute, if I may.....

I think I may be on to something here, if my memory for TPI specs is correct.

Both your cars are automatic, correct? Well, on the 350 TPI that's how they all came from the factory, but the smaller 305 TPI cars that used automatic transmissions often had other built-in restrictions in their design. They were the joe-average entry-level performance V8 cars of the day and GM didn't want them belting out enough power to hang anywhere clost to a 350 TPI car.

The earlier TPI cars (89-down with a MAF type FI system) the 305/auto cars got a MUCH smaller cam installed them that either the 305/5-speed or 350/auto cars did. But in 1990 when they switched over to the speed-density type TPI systems GM CHANGED THE RESTRICTION POINT on the 305/auto cars. GM put in the good-guy cam in ALL 305 TPI engines but when backed with an automatic trans they then slapped on the horrible single 2-1/4" exhaust system and smaller manifolds used on the pathetic low-performance 305 TBI cars. There were, I beleive, options to get the high performance dual-cat exhaust system on your car but the vast majority of the 305/auto cars got the crappy exhaust.

Do yourself a favor and peek under there for us, won't you? If you've got the tiny little 2-1/4" y-pipe and slip-on 2-1/4" cat then you have the common "low output" exhaust on your car. That exhaust is horrible even on a wheezing 305 TBI engine so I can imagine it would just about strangle the life out of a TPI motor!

That could account for a good portion of the dramatic difference in power you are feeling between your two cars. Not all of it, but certainly a known restriction point that could be addressed without even digging into the motor.

Rear end gear ratio differences also make a dramatic difference in the "feel" of the car in cut-and-thrust driving, even with identical engines.

Mudweiser_Matt

Damon, sounds like you know a thing or two. My 5-speed feels peepy to me, the only way I'd want an auto is if it had a good size stall.

83 Crossfire TA

iTrader: (2)

Ask around, try asking at the local speed shops to see who they recommend since there is a bit of an art to it, you could do everything perfectly and still have a funky install where someone that has the feel for it will get it right. Expect to pay about 5hrs labor for a drum brake rear, 6 for a disk brake rear from someone that knows what they’re doing. You’ll find people out there that will charge like half of that, but they’re the ones that I’d avoid. The cheaper places usually rip them apart, and then reinstall the new gears with the same size shims as what came out and pray for the best. That works about 70% of the time, but when it doesn’t the guy will never get it right. The more expensive shops measure out “what should be” the right shims, assemble the gear with temporary bearings, check the backlash and pattern and the disassemble, adjust the shims for what they got on the test assembly and reassemble with new bearings (basically, to do it right you have to do it 2x).

Parts should run you about $140-260 for the gears (white box Richmonds on the cheap end, Motive/GM on the other end) and about $30 for a partial install kit (basically, shims, crush collar and nut) to ~$125 for a full install kit (add bearings to the partial, I’d suggest that unless your existing rear has low miles get the full in stall kit).

Yes/no/sort of… For example, the crank is the same PN, but they have different counterweights on them are not interchangeable with out a lot of balancing work and $$$ heavy metal.

Huh… so tell me, why did a bunch (if not most) of the Chevy entries in the first engine master’s challenge start with 307 blocks if 350’s are superior and 307’s the worst of the bunch? Or for that matter, why are the bore/stroke dimensions of most of the newer LSx style blocks closer to that of the 305 then a 350? (I’ll give you a hint, I’ve answered this in previous posts in other threads)

See above… I will add that there is nothing wrong with the richmonds from a quality standpoint, but I wouldn’t recommend them in a street car unless the owner knows what they’re getting themselves into. The actual gear teeth are cut differently then say a set of GM motive gears. It’s claimed that that way of cutting them is slightly stronger, but whether that ends up the case or not, they do end up louder also, they are more likely to whine even when setup perfectly.

Hey, depending on the year, in a lot of cases, the 5 speed 305’s are only 5-15hp down from the 350’s from the factory. In a lot of cases (and this is true in general with how most cars feel on the street), there is a bigger difference WRT to feel based on gears than actual power. My 308 geared 305/5 speed 87 TA feels like a dog off the line compared to my 3.27 geared ’87 Formula 350 even though there is almost no power difference, and the 3.45 geared 305/5 speed cars are can embarrass the 350 cars easily with a good driver.

Mudweiser_Matt

83 crossfire,
I raced a 4th gen formula (convertable & auto) and had a car length on him until the top of second and then he past me. And I was fish tailin a hell of alot more than he was. And that's the god honest truth!

8T9 BANDIT

305 + TPI + PROCHARGER + 373 POSI + GOOD EXHAUST, STALL AND BEEFY 700R4 = ONE HELL OF A COOL MUSCLE CAR..
JUST FELT LIKE WRITING THAT ?, THATS WHAT MY CAR IS GETTING RIGHT NOW.. CANT WAIT TO GO TIRE SMOKIN IN IT..
----------
OH SORRY ITS NOT A 350 GUYS, BUT IM WILLING TO RUN, ANY OFFERS??

Mudweiser_Matt

Hey Bandit,
$100 say's you'll beat me!

83 Crossfire TA

iTrader: (2)

Hey, towards the end of it’s life, my 305crossfire/A4/3.42 geared TA was running 13.8’s with 2 wiped cam lobes. Prior to that it was a low 13 second car, and the thing was that the thing had stupid low end torque compared to either of my TPI cars (it was actually much happier with the original 3.23 gears and 27” tall back tires). That car was fun to surprise the 4th gen guys and the occasional ‘vette with.

If I was going to build up my current 305 TPI car for NA use, I’d probably stick 4.10’s in it, run the 275/60/16 DR’s that I have in the garage, keep the lightweight aluminum flywheel that it has, some 1-5/8” headers (long tube if I decided to keep the ride height reasonable) some heavily worked 602 heads, a cam somewhere in the 23x duration, and some hand porting of the intake, TB airfoil, decent cold air intake....

I’m pretty sure that I could get that into the low 12’s, if not the 11’s

irocman88

actually i'm pretty sure the 3.7 inch or so bore is what causes the power issues. the bore is too small to create as good of flow with big valves(causes valve shrowding). and the combustion is all different. A 302 has the 4 inch bore, and is actually quite preffered over a 305. same deal with a 327. i'm not so sure the cubes is the issue. IMHO, the 4" bore is the key to power. Cubes are for torque.