General rule of thumb, for every point over 10 to 1 take the CID and multiply by .7

 

On any of these forums about cars and performance mods we have many individuals from many walks of lifes. Some of you on here can afford a frame off $100K resto. Some of you can afford to do 3 or 4K a year and take 10 years. Some can put at $30K build between the fenders, some can budget $3K. The point is at the end of day we all share the love of having a bit more power. If you come to me with a $6 budget, you will get the best parts money can buy within the budget. Now if your goals exceed what I can design with in the budget you will have to make some compromises. If not I can't help. I'm not going to disappoint you and I am not going to reuion my name.

I had a case not long ago where the customers were told they needed $6500 in parts to build a 700HP 540, customer had short blocks together. I sold them $4500 in parts and made the 700HP.

I was once told, chris don't kill the cow, just take the milk. That's how I look at things.

 

He sells them. Patriot went out of business. He'll set them up for what ever cam specs you intend on running. They'll even do some porting for extra money. I've not used those heads, but they seem like "the" budget head.

 

You look at all the l48's that have the top end replaced and they seem to last. I put 10,000 miles on my modified l48 before I built my 400, it was still holding up well and I don't see any of the folks that build their l48 stating that it was a mistake. not for sure what it made at the crank, but through an auto transmission I was putting out 260 rwhp. This doesn't mean that they'll take infinite power, but I'd figure that 350/ 375 should be ok.

 

I don't disagree. If I had a L-48 engine and wanted more, then building up the top end to get a little more is the affordable way to go. It is in fact what I started out to do just a year ago.
Just saying if I actually spent the $$ and purchased an engine I would want a better platform to start with to get what I wanted.
A way to get the CR I wanted with the pistons and squish I wanted with an RPM limit that I wanted to spin, etc. Maybe a good junk yard engine would do well or a budget crate motor that already makes 400HP, LOL, there is another gamble.
These engines are cheap and that always makes me suspicious, maybe they can do more than I think they can. It would be interesting to see. If you can get 350 HP and a good running engine for 3K all said and done, that's not bad, and it's a new engine.
I know me however, and soon enough that would not be enough and I'd be looking for more like 450 HP. Although really if a guy can get an engine to make power at the right places in the rpm range then 350hp would be very nice for a street driver. I doubt I'm making much more than that now, but it's where and how it makes the power that makes it fun to drive.

I think it's great that Straub can take what a guy has and get him where he wants to go or at least let him know how far he can go with minimum $$ and still have a viable engine when all done. That is what I call good bang for your buck, and no cows died in the process.

 

Yeah that's my problem too. A little is to much and a ton is not enough. It always starts out feeling like you arnt going to need more, but down the road it's a different story. That seems time be the case with most gear heads. I read somebody's signature on one of the other forums that said '' when you know that the worst possible consequence could result from mashing the pedal to the floor, then you have enough power'' which pretty much sums it up. You start out with the 180 horse that gm put in the vette originally saying if I only had 100 more horse, it takes off like wild fire from there & doesn't stop, the curse is an addiction, I'm an addict.

 

Wading in carefully here

A couple of thoughts: I agree that first step is to get everything you have working right - headers, free-flowing exhaust, good tune, etc. You'll be surprised how much SOTP improvement you get. Tired carbs, poor tune, restrictive exhaust...it's amazing how much power and driveability can be lost with relatively small things.

My general guideline is that if you're going to crack the engine, targeting anything less than 1 HP/CID is false economy. That level is relatively easy and cheap to get, and it's powerful, responsive and very street-friendly. This remains true up to about 1.2 HP/CID where things start getting expen$ive and somewhat less Sunday drive friendly. Conversely, building too much power on top of a cast piston/cast crank/stock block, etc. OR a chassis with tired suspension bushings, tired brakes, skinny tires, etc. also doesn't really make for a good combination. Balance in all things

The most common mistakes I see, and I sadly see a bunch of them, include:

Overbuilding: "Moar Power" is always an attraction - and easier than ever to get. 500+ HP is now relatively easy and relatively cheap as compared to a decade ago...but you need to ask if you, the car and the way you use the car is up for that. Primarily, don't build a race engine for the street...unless you know exactly what you're getting into.

Mis-matched combos: 220cc intake runners...and a cast-iron, low-rise intake. Tunnel rams on 882 heads with the "390" cam. Cams that make peak power around 6,000 RPM...with 3.08 gears. Not even sure where to start here. For the most part, this stuff isn't rocket science - flow makes power, cams determine where the power gets made, shortblocks support the power level and the rest needs to match. You don't need math to 3 decimal places to make power up to about 1.2 HP/CID...some very simple rules of thumb and common sense based on experience will get you to within a couple of percentage points of "optimal".

Buying for "The Next Build": Probably my biggest irk, simply because I've seen so many people get screwed by it. Someone thinks they're going to build something huge "in the next year or so" and so they buy a huge top (and worse, a small cam) for a crappy shortblock. They end up with a turd engine that just doesn't work right...and then stuff happens and that "next year or so" turns into 2, or 3 or...never. Or, worse - as they start spec'ing the next big build they find their interests or targets are quite different...and so the parts they bolted on the turd aren't really what they want and so end up on racingjunk for pennies on the dollar.

So generally speaking:
1. Determine your HP level.
2. Select heads that deliver the level of flow required to deliver that power.
3. Make sure the rest of the combo is up for your target power levels.
5. Select a cam matched to the heads.
6. Profit.

 

Im a fan of build the next engine first. Build it to with stand abuse. It may initially cost more but in the end your money ahead. We've discussed this some before billa and my thoughts are always bullet proof bottom end, but what power level are you comfortable with cast internals?

 

they also used head of different cc, due to this the test isnt a fair comparison. There is no way a 170cc head or 200cc head would perform best on a 350 with a cam. They should have used the same cc for all heads.

 

Dumbest advice ever agreed.

Yeah spend all the money for THIS build to ensure it doesnt perform." Youll grow into it" Huh?!

 

Thats my point of build the next engine first. Off topic, not that this thread hasnt went south, but you ever get the camino to the track?

 

There are a lot of variables here, but here's my thoughts based on what I've done and seen.


Cast pistons, 1 HP/CID. Period. They're fit brutally tight and I wouldn't turn them very high or put much power at all on top of them.


Factory cast cranks about the same; aftermarket quality cast cranks up to 1.2 as an absolute max.


No such thing as "cast" rods, but the GMPP powdered metal sintered (PM) rods even GM won't run past 450 HP. Even that power level seems nuts to me given the ready availability of cheap, excellent rods. Scat is pretty much my standard and I even keep a couple of sets on hand.


Now...two things. First, there is a world of difference between something "off the shelf" from GM and a quality build - main bore alignment, bearing clearances and quality, balance, etc. I would push a built engine a fair bit further than one of these GM 260/290 engines. They're not bad engines, but they're not built for 450 HP. Same for an L-48; great engine, but components and age are not on your side for major power.


Second, the SBC is a tough SOB and there are always examples of it holding up under stupid power. I knew a guy that dragged an LT1 383 with external balance aftermarket cast crank, hypereutectic pistons, AFR 195s...and a 250 shot. He ran it hard for like two years before it grenaded, racing just about every weekend. OTOH, I helped a guy put in a "cheater" NOS system that fit in the air cleaner and gave a brief 100 (I think?) dry shot...and he blew up his stock '74 350 the first time he used it.


So as I've said many times, this is all about risk. If you can afford to break it, then go for it. If not...might be better off staying within some reasonable limits and putting aside money for a better build. But I certainly don't subscribe to the concept that every shortblock must be all-forged.

 

I know you dont, bu t if you can afford it and you intend on abusing why wouldnt you? I know, im part of the moar is better crowd.

 

always build bottom end for nitrous.... cause if you've never sprayed...you dont know what youre missing !!

tune your AFR on the motor WITH EXAUST TEMP TOO !!!!!!

...then increase spray ..start at 50 hp..look at data logging through the RPM..make sure you stay fat on the AFR..all the while adding a 50/50 methanol/water mix...that sprays with the nitrous... think snow performance..

Go up 50...hp on the shot..watch not just AFR..but exhaust temps...

Spray more...50 shot more...

Always consider a wet system... i know dry systems are in vogue...but they increase the fuel by an adj fuel pressure regulator..when the spray goes on... and not all injectors perform...as pressure increases.. retard timing, some as increase spray..but if aluminum heads...not as much..and with methanol..not as much.. i know guys spraying 200 on keith black (weak) pistons...all day long with 36 total timing... and methanol injection... and thats on a 10:1 motor...

See below video.:

http://fuelinjectorconnection.com/sh...php?groupid=72

Keep that option on the table always !!

 

If someone has unlimited funds, sure. Otherwise...not so much. It's not about abuse, it's about how much power you're going to make and how you're going to make it. Certainly if you're going to spray or go forced induction it's a requirement...but in general, those engines need to be designed for those applications to make the power they're capable of. "Bolting on" spray or forced induction after the fact takes fairly serious compromise...as we see on here all the time as guys try to figure out how to drop that 10.5 CR to 8 for a blower


In my experience, it's another aspect of building "for the next build". Look...for all the talk about building engines, most guys - not all, but the vast majority, are only going to build a couple of engines...a significant portion will build just one. Maybe they'll do a top or add spray...but more commonly, not so much.


Let's say a guy is going to make a 425 HP 383 - does that really need to be all forged? Hypereutectic pistons and a good aftermarket cast crank in a stock block will make a solid, reliable engine at a great price...and leave money for chassis, suspension, brakes, wheels, tires, paint...all the stuff these cars need

 

I take it you like nitrous?

 

hahaha sorry bluedawg....yeah...

 

No worries. My once a day attempt at comedy.

 

No N20 for me too addicting lol

 

I researched it some. I dint like refilling bottles, not to mention all the cars burning up on the line from n2o on youtube. I could see the initial cost not being great, but the long term adding up.