Reddeath210

iTrader: (1)

So i recently removed my 350 sbc from my trans am. I am looking to rebuild the engine and make it a strong engine with a decent amount of kick.

My question is, that if i was told correctly engines are all about what their built with and the parts pairing together well. So what should i look for to determine if the parts i have and pick out will be a good combination.

like how do CFM's affect things, and boring sizes. Any input helps thanks

sofakingdom

iTrader: (1)

I would add a 3rd factor:

The level of attention to detail in the prep & assembly.

What most often seems to happen is one of 2 things: people go out and buy the cheeeeeeeeeeepest thing they can find that says "rebuilt engine" in the ad copy, then try to slide a race-only cam into it, rawhide and gearhead the thing until it's nothing but dust, and then wonder what just happened; or, spend giga$$$$$ on bottom end parts under the hallucination that it's "insurance", then slap em together under their backyard shade tree and throw the cheeeeeeeeeeepest smogger garbage heads they can find on CL on it, and then wonder what just happened.

Boring sizes affect NOTHING WHATSOEVER as far as power output is concerned. That's something you do to restore the cylinders to ROUND and STRAIGHT and POINTED AT THE CRANK. The increase in CID is trivial and irrelevant.

Best way to approach it is, set a goal; (a power #, a lap time, an ET, whatever) then establish a budget based on what you think it's going to cost; then double that; then set aside an additional 50% of that for improvements you hadn't thought of (gears, converter, etc.); then DON'T BUY ANYTHING until you have AT LEAST THAT MUCH sitting in your bank account that you can freely spend without worrying about the rent.

Survival comes from the short block. Power comes from the induction system (heads, cam, intake, exhaust). Speed comes from the drive train. Reliability comes from attention to detail.

If your project comes up short in survival, power, speed, or reliability, you know right where you didn't spend enough or either time, money, or attention.

Base91

iTrader: (1)

And you have to be honest with yourself which may not always be easy. What are you REALLY going to do with the car? How much time/money/interest etc. do you really have? Can you handle it (financially etc.) if end up in one of those "what just happened" situations. I've found it's easy to get carried away and take on too much too soon. Especially if you're relatively new to doing this stuff.

Ozz1967

iTrader: (4)

This is....awsome! This statement alone should be stickied in the Engine Build/swap sections! I don't think it's ever been explained quit that well or bluntly! The second paragraph I may just put in my signature.


What Sofa says is correct. I didn't double my budget, nor did I add the extra 50%...and my wife has been mad for the past three years! Learn from this.

92droptopws6

iTrader: (10)

Agreed 100% with the above....
Matching components that compliment each part of the build.. Too many people open a cam book and look at the bottom of the page for a BIG cam there are many documented builds from reputable builders such as: LPE,TPIS etc. That make very good power that wont break the bank.
Compression makes power
Aluminum heads allow the use of higher compression: ) 10.5-11.8 (pay close attentiin to your projected build and intentions of your build here)
Induction type EFI or Carb
Camshaft very important, stay in the reality of the performance level
What size stall is good for street/performance driving? Unless you are a manual.
Are you building a double duty car street/strip?
What is your RPM range
What gas are you planning to use?
What gear ratio do you need to run?
So much more info that needs to be thought about in the process but you see where i am headed.
My quickest stock shortblock L98 was back in 93, it had a 560 lift roller cam,1.6rr,vette heads WORKED,superram,30lb.inj..,58mm,Hooker shorties,2800stall,3.42 gears,pulleys,performance resource chip.....etc. ran consistant 12.7s 1.7 60'on radials then the 700r4 broke AGAIN!!!!! So it became a T5 car, that was the best conversion EVER, i went from 12.7 to 12.1 could NOT buy an 11 second pass though!!!!!!! Slicks and a stick....

Mrbanados

How much power were you putting down?

sofakingdom

iTrader: (1)

I should also have mentioned:

Attention to detail is what sets one project apart from another built with the EXACT SAME parts list. If you ever wondered why 2 extremely similar engines can run WAY different, THAT'S why.

Details like zero-decking the block to the rotating *** to get rid of deck clearance, ring gap, torque plate bore & hone, indexing the crank, boring the cylinders on the correct centerline instead of the wear, installing the cam bearings in the proper orientation, removing all sharp edges from everything in the combustion chambers, careful valve spring and valve train geometry setup, ... the list just goes on and on.

92droptopws6

iTrader: (10)

There were not many chassis dynos in early 90s, we went to the track. So i would have to say it put 345-350 to the tire weighing in at 3680 w/ driver i could be off it was plenty to run 12.1 at sea level.

Reddeath210

iTrader: (1)

Thanks for the tips everyone appericate it alot

grumpyvette

http://forum.grumpysperformance.com/...hp?f=69&t=9930

1gary

Trust me.I'm being polite here.Sir I don't like guys that come on a site and promote their own site by posting a link.I think it is rude.
So I am letting you know that I have reported it and leave it in the hands of this site's management.

1gary

Here what I want to know.If I throw some necessary formulas at you,are you willing to learn from them??.

IROCtheThird

iTrader: (15)

Did you even read it? Its a 2 paragraph article talking about what makes a good engine. Its not like he's advertising things for money. The way I look at it, is its just like when someone posts a link to an article on LS1tech, FullThrottleV6, Yellowbullet, etc etc... If you actually opened his link youd see it was a forum.

Neal301

I agree with you except that the link he posted was relevant. Would you rather have him type it all up again? It is useful information and I actually bookmarked that link and im glad he posted it.

Reddeath210

iTrader: (1)

Post away i am willing to learn, just for reference I am looking to build a street car something with a decent amount of horse

Neal301

You will need:

Performance camshaft, if its a TPI, grind out those damn bumps in the plenum, better gears (I use 343 but thats just because I dont want to loose massive amounts of fuel econ), better exhaust system (including headers). A lot more than the engine goes into making a good car. Sorry I didnt post specific parts or anything but thats up to you, its your car.

I'd start with the TPI plenum (if its a tpi), if not do the gears because thats the biggest pain in the *** in my opinion.

Reddeath210

iTrader: (1)

Carbed thankfully

1gary

I think "the tune" begins with the build sheet and not afterwards trying to make up for poor planing of parts purchases.

So to start you have to plan plot out a power curve and something on today's pump gas won't detonate.

It is proven fact the smaller the engine,the higher rpm is required to get to it's power curve.The old saying"there isn't a replacement for displacement" is very valid.If it is a question of 350 vs 355,then ok,it isn't significant.But if it a question of either 350 vs 383 or larger is certainly is valid.That larger engines are more accepting of bigger cams/different cam timing and still having a decent lower more applied power curve in a street vehicle with good driving manners.Also when it comes to a increase in SCR it certainly does effect the level of power output of a given engine.A good safe guideline is 9.5 for cast iron heads and 10.5 for aluminum heads which dissipates heat better.Now you very well might see guys post about their marginally high SCR engines and not having a problem.The thing that often doesn't come to light is the amount of concessions they have to make either in cam timing bleeding off the higher SCR or in ignition timing and those concessions actually resulting in a much lower power output vs if they have built a matched parts build in the first place. So SCR is this formula.

http://www.csgnetwork.com/automotiveconverters.html

Page down to the compression ratio calculator.Notice a number of useful formulas on this link and I suggest you book mark it.When I talk about "SCR",I'm talking about Static Compression Ratio". It is the mechanical compression ratio.But engines don't operate like that alone.But need that formula to figure out the DCR which is this link:

http://www.wallaceracing.com/Calculators.htm


Page down to Dynamic Compression Ratio or DCR.It takes into account volumes and cam timing events.Here your looking for a DCR of about 8.5(don't let what appears to be a low number scare you).

There is a value in machining of the deck/piston and rod length choices that results in squish/quench.The target you trying to hit is .035 to .040.Here is the formula for that:

http://www.crankshaftcoalition.com/wiki/Quench

Trust to hit those targets,it is a tool to use in a matched parts build that is a anti denotation tool and helps promote flame travel which results in a high engine output.And while I am talking about denotation,the guys that in a odd sense who are actually lucky enough to hear a engine knocking we also know that denotation can be happen in the higher RPM ranges undetected where it is not discovered until there is a issue where a trouble shoot finds the results of it,then way late where engine damages can be serious.

You want to match the intake runner size with the size of the engine.My experience of many,many,yrs of building engines is a minimum of 180cc's for a 350/355 and a minimum of 195cc's to 200cc's for a 383 to 406.You can somewhat plot out a power curve with these choices of heads.Well that and the cam choices.Note:Intake runner sizes advertised are only a guideline for two reasons.First,the cross sectional part of a port and it's shape is closer to the reason why one head might be considered hot and another head a turd.Most are done on a air only bench testing and for sure the way a engine operates includes introduction of a fuel which is a game changer.So the use of a "wet test" is a way to get closer to what you have.R&D with yrs of experience is why head porting is best left to the pro's.Yeah,yeah,I know I am ticking off a bunch of guys with home Dremel
caveman carving porting who often don't have use of the basic air flow bench,let alone wet testing and certainly don't have 5 axis programed CNC machining.Where the home porter might think shine is best not knowing what to do where and actually are doing more harm than good,let alone coming even close to matching ports.I am on solid ground on these logical reasons all the porting books being sold today aside.The sole reason why for back in the day home porting to today's much higher engine outputs is cam and head R&D.

Cams need to be matched to SCR's.This link provides you with that:

http://www.crankshaftcoalition.com/w..._compatibility

Now I think the cop out of it's only a street car is one of the reasons you find outstanding performance of one car and another one being a turd.

Due to serious carpal tunnel hands the hurt like hell,I'm going to leave it here.There is a bunch more which at a later time I am willing to share.


Side note.I want to get out front of me using the above links.None of them am I a Owner,Admin,or Mod.I have no absolute self interest in promoting and there in lays the difference what I posted about earlier.Just passing along the info to help this O/P out.

1gary

Also a good read:

http://www.enginebuildermag.com/Item...spx?MostRead=1