Just out of curiosity: What do flat top pistons and an RV cam do when placed in a v8 for a fiero conversion? I know it's more hp but how exactly do these items improve engine performance? If know, please let me know. Thx.

NO NO NO. An RV cam is just that. It's for trucks/RVs. Designed for low RPM torque and pulling power. They fall off very quickly as RPMs increase. Trucks are not sports cars and spend their life at low RPM. You will blow away Vettes off the line but you will be done by 2500-3000 RPM.

Choice of piston crown type is based upon your desired compression ratio...flat top would be favorable for a turbo application while domed pistons are good for a high performance, normally aspirated engine.

Most of the regular 350 engines use dished pistons for low compression in order to run on any regular pump gas without pinging. Raising the compression adds power. Flattop pistons put the compression ratio right at 9:1, which is about the most you can go without using expensive racing fuel blends or adding octane booster. You should still use premium gas with a 9:1 ratio. I'd avoid the domed pistons, mostly for racing.

An "RV" cam is a generic term for a cam with a short duration (like a stocker), but with a little more lift than normal. Tom is pretty much right in his assessment. But, you don't want to go with too much cam either or else you'll lose a lot of that torque that V8's are famous for. I've had lots of small block Chevy hipo building experience, so I might be able to suggest a good cam grind for you if need be.

Let me know what type of performance you want and which tranny you're using. Is this strictly a daily driver? A weekend warrior? High performance playtoy? High RPM Vette killer? Mostly city driving or mostly open highway? It's not an easy task picking the right cam. Good luck.

I agree wit doze guys

Archie

Thank you all for the input. I
am glad the RV cam improves performance at the lower rpms for off the line quickness not high rpm runs. Reason being: safety. My assumption is that if a car is pushing higher speeds at higher rpms, it's too tempting to go too fast. My best thrills is taking off quickly from 0-30-60-75 and stopping about there.

I have no intention of racing vettes at 90-100+ mph! But it would be fun to beat them off the line...I am sure gear ratios play an important part in all this too. But low end power is what I personally like.
Since we don't have an autobahn, 1/4 mile runs are more fun, for me anyway.

I disagree with doz guyz!

An RV cam is a cam with aprox. 224* duration @.050 what a RV cam will do is boost mid-range torque (were you actualy drive your car)
For example I had a 73 Nova with 214* IN 220* EX .440 IN .455 EX Adv. 106*
I am at around 4300 elv. I ran 12.37 in the quarter at bonneville (RMR) that is around 11.37 sea level.

As for compretion we Utahns can get away with more compretion due to the fact there is less dense air at 4300 ft elv.
You can run one point more at 5000 ft than sea level. So for use we can easily get away with 10.3-10.5 compretion on pump gas. Now if you realy want to be on the safe side i'd run 10.0:1 compretion with fast burn heads!

Sorry dude, I don't care if you do livc in the mountains. If you run 10:1 or higher and this is a daily street driven engine, then you're going to have problems eventually if you don't run high octane gas. Can you still get 96 octane on a regular basis? Around here you're lucky to find 91-92 octane. Ever see a hole in the top of a piston from pinging? I have. If the 350 is bored out, this raises compression some more, even with flattops. Also flattop pistons have better combustion (flame travel) than dome pistons.

There is no standard grind for a RV cam. Generally they do boost low and mid range torque. By the way Zorba, I like the way you think. You want maximum torque at about 4 grand with a big fat flat power curve. A cam with 224 degrees of duration at 0.050" is hardly a RV cam unless it's in a 454 or something. Most RV cams I've seen have lots shorter durations than that. Zorbie, email me and I'll run some simulations through Desktop Dyno for you.

Not to be too off the subject here but aligning that starter motor to the flywheel is a total ***** ! I have to start playing with shims now to see if I can adjust it right! I am doing this before putting the tranny on and the engine in. makes it a lot easier! When it's not one thing, it;s another.

No, an RV cam is a loose term used to describe a cam used in high performance towing/offroad vehicles period! It's like a 3/4 race cam! What are the exact specs on a 3/4 race came? No one in hell knows! LOL It's all old school generalities!

Batboy, if you read my above post I did not recomend domed pistons I recomended 10:1 ratio with fast burn heads! ie: 64cc swirlport designed heads! Flat top pistons actualy 2V relieved. Let's not forget the differance between static compretion and motor compretion.

You keep building your engines the way you do. I will keep building them my way.
Sad thing is I beat every one who thinks the same as you! Idealy you want your peak torque above your rmp drop from 1st to 2nd.

Ignorance: To ignore the truth!

Technology has changed alot in the last 50 years!
Food for thought Hondas run 10.5:1 no burnt pistons at sea level hugh thats funny?

Anyways to avoid writeing a book, go read a few if you don't belive me.
Hell if you don't have the coin for some new books the intenet has a wealth of knowledge at your fingertips!
www.kb-silvolite.com
www.off-road.com/hummer/tech/power.html
www.vettenet.org/torquehp.html

Pay special attention to the last link.
But in the end they will still never learn?

[This message has been edited by FIEROCIOUS (edited 11-15-2000).]

Hey ferocious...you spoke like a true Utahn!
Man...pay attention to your writing. You are sounding "self-righteous" with batboy. You can express an opinion without this "your wrong, I'm right" way of communicating.
What I mean by a true Utahn is simply this:
"not knowing how to interact with someone who has a different opinion than your own"...
After living here for 13 years, I have learned this sad truth. Now, don't give me the "go back to where you came from" crap about this. That's also Utahn's way of dealing with differences. Anyway, back to the motor thing. No offense intended.

The 350 Chevy engine that is in my '87 SC has a cam in it that was for towing a trailer. It has a LOT of low end torque. My 1st gear has to be shifted almost immediately. When I hit 2nd, 3rd, 4th I'm long gone I just use 5th to back off if I'm goosing it. When on the freeway or any higher speed road I stay in 5th. I haven't had to downshift yet when passing even on a hill. It's a totally different world with a V8.

Sorry, Sorry, didn't mean it that way, I just get tired of people who refuse to learn more about the world they live in.

It just sadens me that people can't take five seconds out of their little lives to read and learn, instead they speak of things they know not of and perpetuate the ingnorance.

I take the Utahn crack rather offensive! I am a COLORADOAN!! And proud of it! Utah Sucks! I wouldn't be here but for my wife!

Anyway, I have said this time and time again we can discuse, argue and debate all day long you will still be right, I will still be wrong.

And like every Utahn refuse to even for a moment contemplate the validity of my side of arguement!

The above post was directed more at people in general than at batboy,

Sorry Batboy if you took it that way.

quote Originally posted by FIEROCIOUS: Sorry, Sorry, didn't mean it that wayI take the Utahn crack rather offensive! I am a COLORADOAN!! And proud of it! Utah Sucks! I wouldn't be here but for my wife!

Utah is different than any other state. I have never been to colorado (other than the airport)anyway. No offense taken by me or no offense directed to you. My wife and kids are from utah so I stay here. This is off topic...I am now in the process of installing my new v8 and got stuck with the alignment of my starter gear to the flywheel.
Any experience here?

Hey, no offense taken at all here. Everyone has a right to their own opinion. There are hundreds of ways to build a small block Chevy 350, mainly because there are more high performance parts available for it than any other engine. There is no completely right way and there is no completely wrong way.

Fierocious and I will have to agree that we disagree about what compression ratios will work with pump gas and still provide longevity. We do agree on one thing though. Heads are the key to power and better flow with a small block. The old style stock heads suck in the power department.

Yep, I'm old fashion and proud of it. I just pulled out my book by John Lingenfelter titled "On Modifying Small-Block Chevy Engines" published in 1996 and it pretty much says what I was saying. The book also says that with aluminum heads, you to run a little bit higher C/R.

Fierocious is talking high tech and high dollar engines. I can build a 350 engine for about $2,500 that produces 350 hp and 400 tq that is reliable, uses pump gas, and is driveably in city traffic. I was under the impression Mr. Z was wanting a high torque, low budget engine such as this. Or you can spend several times that amount for only a little extra power like Fierocious.

Trust me, the ol' Batmobile Fiero with a tired, worn out stock 350 is still a blast to drive. A freshly rebuilt stock 350 would be awesome. A 350 with even some mild mods will be unbelievable.

Friends???

Batboy probably has experience with the fiero trannies and starter alighnment.

The above listed Nova I mentioned cost approx 1000.00 to build complete! the kit came from Northern Auto Parts and I did the machine work my self in high school auto shop!

My teacher thought "old school" before I built my engine. After he saw and experienced what I did on that engine he now teaches a differant lesson.
The student taught the teacher!
He has been raceing Mopars for some thirty years and my little 350 bested his 440's!
Unfortuneatly his Hemi still kicks my arse!

Anywho, Eddlebrock back in 1933 made a head for a flathead ford called the "Denver" What was it? A higher compretion head to use on the SaltFlats due to the higher altitude a higher compretion ratio could be used.

In laymen terms there is less air up here in the mountains and and less air to be compressed in the cylinder bore, thus a 10.0:1 compression ratio here at 4300 alt. is like 9.2:1 at sea level.

When dealing with heads remember volocity is far more important than net flow! Don't hog out the ports like so many "rodders" do.

I've said my peace.