[font size="1" color="#FF0000"]LAST EDITED ON 27-Sep-01 AT 05:51 PM (EST)[/font][p]I have heard that a GM 350 has a 4in boar, and 3.5in stroke. If you do the math(2 x 2 x 3.14 x3.5 x 8) it comes out to about 351.68cu in. A freind of mine is really proud of his Bronco, which he has said has a 351 and thus brags about his extra cubic inch. So, does anyone know if the GM 350 is actually 351 or what the bore/stroke is? What about the bore/stroke for a 351? 4 x 3.5?

I plan to eventually buy a pontiac firebird(call me a trader), and so I have ben looking for cheap easy HP upgrades. First on the list is a Flowmaster muffler, and I have found one for 79.99 at http://www.promax.com does this sound like a good price? One web-site claimed that a muffler added an extra 30HP from their dyno tests, but that seems a little high, right?

I think the next thing would be a cam. However, I have no clue what to look for. Looking at pro-max again, they have comp cams, and they show an RPM range, and gross lift. I'm assuming the higher the gross lift the better? What about the RPM range? I don't have any clue what the RPM range could be.

I think that a rough idle(as advertised on pro-max) would sound horrible for a 90s bird with flowmaster, is a rough idle just a side effect of any cam? Where should I look for cams that can produce power and have a smooth idle?

My last qestion, could I get away with just switching the cam, and what has to be done to switch the cam? Take the valve train apart, pull the pushrods, switch the cams, put everything back togther, and enjoy the results?

Logan

 

The SBC has a 3.48" stroke. Actual displacement 349.847 cu.in., like it matters.

 

Logan, the stroke on a chevy 350 is only 3.48 inches. Also there is no such thing as 'cheap and easy' horsepower on a C350. There just isn't much engine to work with. If you spend some serious bucks you can get 450 hp from one, or even more, but it does take money. As for the cam, a smooth idle and lots of top end power are contradictory goals. A roller cam would give the best results but they are also the most exspensive. DF

 

I'm deffinatley plan to add the flowmaster muffler. I'm assuming $80 is a good price. I don't know how much hp that should add, but I want to get up to say, 310hp(because LT1s have 275 and LS1s have 310).

So, I think the next best thing to do would be a nice cam, which pro-max has for less than $100. However I haven't tired changeing a cam before, and don't know what to expect.

What web-site should I look at for a good hp upgrade?

Logan

 

Look I'm as "Ford blue" as anyone here but I also try to be a little realistic. "isn't much engine to work with"? What is that s'posed to mean? Like it or not the SBC has been around for many years in one form or another and the fact is it has more aftermarket support than any 3 Ford engine series combined. Is it a better motor than a 351W...maybe...maybe not. Is it a decent motor that can be made to produce tons of horsepower from a relatively small package...yes as can most motors of comparable dimensions with the right aftermarket goodies. I know this is a Ford board but let's try not to steer people wrong just because of our bias.

 

With a some work, the little chevy can be stretched out to 400 or 420 inches, but it costs $$. My FE is already 390 to start with. My point was there is not alot of displacement there, and it is never 'cheap and easy'. If I were going to build a GM, I think I would do an olds, buick, or pontiac instead of chevy. The small chevy has a very short deck (9.030), which means short rods and less than ideal mechanical efficiency. An FE has a 10.17 deck, an M engine has 10.300, I believe the other GM engines are taller as well. The 350C is very common, but if you want power there are better places to start. DF

 

[font size="1" color="#FF0000"]LAST EDITED ON 27-Sep-01 AT 10:58 PM (EST)[/font][p]Dinosaurfan, I will agree with that you that for HP there is no replacement for displacement. This weekend I should be picking up my next car, a Pontiac Firebird with a 350 LT1. I already plan to add a flowmaster muffler(the sotck exhaust sucks, and for the sound, the flowmaster is worth it), I don't have any idea how much HP that should add. One place claimed up to 30, but I dought that much more power.

Logan

 

if you buy a Firechicken ya better hold on to it! if you all haven't heard G.M. is pulling to plug on the Camaro and the Firechicken after the 2002 model year. nobody wants them anymore. CJ.

 

Headers would help and put a true dual exhaust system on it. The thing I like about chevy is most of the parts interchange like the dist. will work in a small or big block and the bellhousings are the same pattern plus the parts are cheaper. What year of firebird? The newer ones would probably benifit from a less restrictive air intake system. Eric

 

"Holley" has a kit called SYSTEMAX II that sells for $1,315.99 (mail order from Jegs or Summit)it comes with aluminum heads, cam and kit, intake manifold, timing chain, head bolts, hardened pushrods, etc. It all bolts to a 350 C*** and makes 420 HP (at the flywheel). Quite a bit more than your $80. muffler but the results will be much more impressive.
Also, don't believe the advertising claims of 30 HP from the addition of a muffler...I'd be surprised if you'd even get half of that.

Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro

 

As tempting as the sytem is, for $1000 I'd rather put togother my own setup. The Bird is a '95(I think someone asked?). I think that a good cam for $100 would be the best next mod. I have realized that the tools around my house are anything but adequate for very srious work. That will probbably chage later on, maybe I can get in shop at school next smester... What would be a good easy mod for a beginer like me for $100? Something that would perhaps add some HP(not a whole lot) and be useable in a future setup?

Logan

 

A 95 would undoubtedly be fuel injected. A performance chip, intake manifold, headers, cat-back exhaust system, all good and easy upgrades. If I'm thinking correctly, those are also a MAF system, not the limiting speed density system like my F150. Cams are easy to change if the engine is pulled out of the car. Only special tool needed other than sockets and wrenches would be a torque wrench and a damper puller. They can be almost if not impossible in the vehicle, not enough room in front of the engine. I've rebuilt a few Chevys with a cheap beam-style torque wrench and puller that I bought at Auto Zone,so tools aren't all that complicated. Car Craft has done a few cheap upgrades on engines lately, all of which would apply to any engine. Pick up a few performance mags, check out a few web sites. Good info can be found easy anymore with the WWW.


88 F-150 4X4 XLT Lariat w/5.0 EFI 5 spd (DAILY DRIVER)
86 Ranger 2WD w/2.3L EFI 5 spd to be 351W 4bbl C4 (NEW TOY- DETAILS WHEN FINISHED)
85 Old Cutlass Supreme 350/TH350 Holley 4160,Edelbrock Performer intake, el-cheapo headers, General Kinetics 270H series cam, 15.588 best 1/4 mile with original 10 bolt 2.41 gears (OLD TOY)

 

A couple things I forgot to say. When a company brags about how much hp their product makes, you have to look at what engine they are using for a test mule. They are usually already bored a little, have a few other performance parts on them, and putting out a good amount of hp already. Also look at what RPM they are spinning that engine. A stock SBC shouldn't be turned over 5000 RPM or so if it has a few miles on it. Cast cranks and pistons don't really like the torture. Also, are those RPM's reasonable for street use? How often do you rev a street car with an auto trans over 4500 RPM? Keep RPM power in the lower areas.

88 F-150 4X4 XLT Lariat w/5.0 EFI 5 spd (DAILY DRIVER)
86 Ranger 2WD w/2.3L EFI 5 spd to be 351W 4bbl C4 (NEW TOY- DETAILS WHEN FINISHED)
85 Old Cutlass Supreme 350/TH350 Holley 4160,Edelbrock Performer intake, el-cheapo headers, General Kinetics 270H series cam, 15.588 best 1/4 mile with original 10 bolt 2.41 gears (OLD TOY)