What is needed for a street motor 455 500hp then 600hp?

...an engine such as this would be an excellent candidate for a heavy car with taller gearing and less gears in the transmission and/or no overdrive, as well as a mild converter with heavy duty hydraulic torque multiplication...even more so in a lighter car, showing that one does not need a high-RPM screamer to go fast with class.

 

JayZee88

Have you figured out what you want to use for an exhaust system?
Will a full header fit or use shorty headers?

 

I am going to use shorty headers and ta 288 92h cam. That should get me close to my power goal with my parts selection without sacrificing to much on the low end.

 

As you probably already know, long tube headers help the low end.

 

Except long tube headers probably will not fit an Electra without modifications.

Shorty headers will work almost as well in this application if an "X" pipe is used to collect both pipes coming off the shorty headers. http://www.v8buick.com/attachment.php?attachmentid=290495&d=1406075541

The TA 288 92H cam has a narrow 110* LSA. We recommended a wide LSA with 113* minimum.

 

Would the low end torque be considerably impaired with the 110 LSA over a 113?
Would different rocker ratios on the intake and exhaust give any advantages with this cam? Like 1.6 intake and 1.7 on exhaust to overcome the restrictive flow going through the heads?

 

The problem is with valve overlap or the time both intake and exhaust valves are open at the same time. There are several things to pay attention to.

JW has observed that for the BBB as the LSA gets wider on a street performer cam the torque curve becomes flatter and wider as demonstrated with the 448 engine where the cam had a 115* LSA.
Others here that have used wide LSA cams in their cars will testify to the same result.

Second, as the .050" overlap increases much past zero the idle becomes more choppy but more important the transition from low rpm torque to midrange becomes more abrupt and that point moves up in rpm.
Example: A cam with 20* overlap has a rough idle and makes very little power below 2000 rpm then suddenly somewhere before 2500 rpm power comes on like someone flipped on a switch.

Third, typically having an exhaust duration a fair amount more than then intake duration will extend the upper part of the power band.

The "X" exhaust pipe allows the left and right engine banks to aid each other in scavenging exhaust.
This X pipe is on a long tube header system but I like the picture http://www.v8buick.com/attachment.ph...5&d=1406075541
JW did a test with a 500+ HP engine and found that the shorty header came within 8 HP of the long tube header

 

The test seems as you would expect.
The question being what is the low and mid torque difference between the LSA's and/or any headers, not the top end.
The description on higher overlap is very helpful to the OP's concerns, it will idle rougher and then come on stronger.
It increases low end torque, despite the description of 'bleed off'.
It will have higher running cylinder pressure from where it wakes up until close to the hp peak (usually).
The way that it's helpful is when it wakes up below the converter's flash speed, which isn't too difficult to do considering the smallish cam specs for a large engine.
I'm not pushing for any certain outcome, only giving info for the OP to decide.
Definitely an x pipe should be considered.

 

In the spirit of giving info I would like to add more to consider concerning cam choice.

For this application High lift shorter duration cams will provide great torque over the widest power band.
If you are using an aluminum head that has good airflow to .600" valve lift and the plan is to use roller rockers which are not restricted to the stock rocker .500" lift, it would be a waste not take advantage of their operating range.
Of coarse having valve lifts in the .550" range with shorter durations and still have reliability over many street miles is best done with a Hydraulic Roller cam.

You also have to be more careful about the oil being used with a flat tappet cam and it is best to use an oil designated for flat tappet cam engines.
Last cam and lifter failure I delt with had imbedded hard steel particles into the piston sides. Block had to be taken down completely for washing, new CP custom pistons .005" overbore so the cylinder wall damage could be honed out.
New cam and lifters and so on. Not fun and certainly not cheaper than if the better components had been used in the first place.

 

That's definitely good advice.

I know the OP has suggested a preference for using the aluminum heads, and there might be a very good reason.
One might be due to lack of a decent starting point with factory iron's and the possibility of the finished costs rivaling an aluminum choice, but in the interests of the build's recommended direction...

I would revisit how well matched the iron heads would be to the cam, intake and shortblock.
Being that CFM is more than met for the power goals, set aside that for the moment and think about how the slightly smaller CSA of a factory head will have more velocity, lower peak torque rpm some, and increase response and driveability, even with the same cam.

It's easier to put the $$ into a well thought out short block that can have the top end upgraded down the line if need be.
There have been many examples here of extremely strong iron efforts, Chris Skaling's builds come to mind.
I would not match up a mild cam with a bigger port.

 

Very good point.

If considering iron heads as a possibility;
Questions would be, what would it cost to rebuild the heads including exhaust valve seats, valves, valve job, do the port work and set the heads up with the correct valve springs?
Who would do the job?
How much to ship a set of iron heads both directions

Now add in the cost difference between the TA roller rocker assy for the iron heads versus the SBC roller rockers for the Eddy Heads and I suspect the Eddy heads come out ahead cost wise.

Also consider that the aluminum heads will allow a higher static compression ratio.

 

Engine/combination specs/details aside, what ultimately matters most is the final outcome and whether or not it meets or exceeds the wants/needs of the operator.

How to achieve these results can vary.

One would want to weigh in the pros/cons with cost and complexity vs what is really desired, and if one would be willing to go over the top with money invested vs returns and decide for oneself if those returns are too diminished to be worth it.

"Low hanging fruit" and all that.

If 525 ft. lbs. over a wide RPM range with 2.5x hydraulic multiplication on a 2.93 ratio isn't sufficient to move 5000 lbs., would 550 ft. lbs. in a narrower, higher RPM range make it better?

I seriously doubt it.

Not to mention all the other woes that come with a low-hanging header (vs shorties/manifolds) in a heavy land yacht that will see regular driving on normal American roads. I think we can safely rule out quarter mile arguments in this scenario...

Would be a shame to bust up a $1,000++ custom set of tri-y headers that would be required to tame an ultra-wild screamer to make it even driveable on the street.

An "X" pipe would fit much better under that car and make shorties perform closer to full length custom headers, although another alternative could be to make the long primary tubes oval for better clearance and fitment, but then you're talking more money for what, 5-10 more ft. lbs.?

I guess if you were wanting 'bragging rights' rolleyes you could spend big money on small (or unnecessary) gains, so the line to be drawn would ultimately be how much money you had to blow, or how much overcompensation you felt was required to make everything look and feel much larger, though this is all just psychological and not very realistic.

Not trying to offer up a preference here, so let's list the pros and cons of different combination choices and which ones would be better suited for this particular vehicle and its intended usage.

Ball's in your court.

 

I think that is what has been done thanks to everyone's contribution.

The OP has block, rods, crank and carb along with car and power train.
Transmission, rear end, pistons, heads, cam, intake manifold and exhaust system has been covered.
Have we missed anything?

The OP has also spent many hours searching this forum on all these topics sometimes into the early morning hours.
Nice Work!

 

I'm not sure what's being referred to as contributing to a narrowed powerband or less streetable.
The entire combo is so mild that little of the sort would be happening.
Smaller port heads vs bigger? Helps everything but might only be wise if he has a good starting point for set of heads.
Longer tube headers? Helps, with the exception of fitment or other implied hassles.
Tighter overlap? Helps, with the cost of less power AFTER peak hp but likely more the entire powerband, and a slightly rougher idle. A non concern with such tame specs. It would hurt if the exhaust was restrictive or the OP didn't bother to port the factory heads though. Dyno results being subjective to said conditions, rather than universally accepted.
X pipe? Helps.

Would a 600-700hp engine with 550-600tq but in a higher rpm range push the car that much harder? Absolutely!!...esp with some rear gear.
Nobody is steering the OP towards that.
What might be achievable with the budget imposed on engine alone, there's obviously much more to consider for the car itself.
Gears, torque and weight are a direct correlation.
More gear makes the car seem lighter.
If anyone has never been in a high powered full sized car, it is an absolute treat!
It's quite a matter of interpretation when it comes to calling it a daily driver :Brow:
Some people enjoy crotch rockets, others enjoy driving miss daisy, lol.

 

I was trying to be facetious.

 

Hey Gary. That's OK

I was pointing my remarks more towards the OP to recognize the time he has spent looking through this forum.
The other night I was up till after 1 AM Pacific time and he was still searching a variety of topics related to his project.

Also wanted to point out that there is very little left to cover at this point and as you put it "The ball is in his court".
One would hope however that if there are any further questions for clarification or otherwise there would be no hesitation to ask. That includes the many others that have viewed this thread over 2600 times.

The OP has an opportunity here to do something special based mainly on the hundreds of hours JW has spent with the many combinations.
This also includes the many combinations that the rest of the board members have taken the time to post.

 

Subliminal suggestion at its finest. lol

1) Suggestions of larger cams with tighter LSAs comes to mind (see above posts).

2) The engine's built already? See #1 above.

3) Better velocity is highly advised, yes.

4) Helps, yes. See my previous post regarding the gains vs cost/complexity, and though are indeed implied, are quite real and worth the examination--not just for initial cost/hassle, but for long-term usage over the lifespan of the system itself, which can include but is not restricted to leakage, corrosion, ground clearance, noise, vibration, etc..

5) See #1 above; Tighter LSAs tend to give peakier, narrower powerbands, and yes it does help with cylinder fill/charge mixture/swirl (but then so does high velocity heads, see #3) albeit in a slightly different way*(see below), gives a similar effect (increased torque); the cost of less power BEFORE peak is also realized, which is offset somewhat by using longer tube headers (see #4). "Slightly" rougher idle (as well as poorer intake vacuum and intake reversion) is subjective and depends on just how much of a difference the LSAs and cam specs are, and cannot be used here as an absolute statement, and could very well be a major concern, since "tame" is also subjective, particularly when larger cam specs and/or LSAs are being suggested, either directly or indirectly as an innuendo of superiority.

As you said, it would hurt in a restrictive environment and would depend heavily on the rest of the combination from the intake to the tip of the long, meandering exhaust system likely to inhabit the underside of a C body GM car. Not saying it couldn't be an option, but the odds of its success are reduced considering this environment and choice of other parts already mentioned.

*knowing that head and camshaft design work hand in hand, this dynamic can be complex and so is not easily explained in such a brief summary, except to make a point of reference regarding torque production.

6) While we're at it, we could say a 50,000 HP jet engine would improve things even further, but since this would be even more obvious hyperbole, let's stick to the reality of suggested parts applicable to the current combination.

7) Nor has anyone suggested anything that would even remotely resemble it (see #6), right? (see #1 and #3 in regards to vs larger ports)

Yes, yes. My '69 Electra was a real blast to drive, and surprised a lot of people. I would hardly call it either a crotch rocket or 'driving Ms. Daisy', though it was a happy medium.

There are many things to consider, for sure. I guess my point to this whole thing is that it seems silly to go off on tangents that are counterproductive to what would work best for the OP's combination, given the desired results and ease/complexity of componentry.

If he wants a 7000 RPM peaky, finicky engine that needs tri-y headers to help it behave with 5.13 gears and 4000 stall in his Electra, then more power to him.

Or perhaps a mild (subjective term, isn't it?), smooth-idling (not so subjective) big block with tons of low-mid torque and a wide powerband used with his current allotment of parts (including the trans and rear gear) would be just what the doctor ordered?

A matter of 'interpretation' indeed.

I guess we can all offer up our suggestions and let him decide which would be best/desired for his application, though I suspect more people here would lean toward the latter above scenario to the former.


Too long; didn't read version: save yourself the trouble and just skip over my posts.


**disclaimer: for entertainment purposes only

 

Indeed sir. This board is a wealth of information and entertainment.

It's commendable and wise to do as much research as you can before committing to anything.

 

Again with cams as mild as what was being discussed, there shouldn't be any risk of it becoming undriveable or 'too peaky', that's a stretch.
I was addressing what was already touched on as the characteristic of it waking up more abruptly when the throttles opened.
There's usually MORE low end torque, but not at idle where it would never be pushing against a converter at...and with obvious deference to the shared combinations, provided they can be EXACTLY duplicated.
Preferred wider LSA might imply ease of tuning and idling, or compatibility with EFI.
It was only pointed out to offer clarity to a question the OP asked, not to suggest any preference.

I used an extreme and exaggerated example of a build within close reach of his budget because he might actually want that.
It wasn't meant to incite extrapolation to the absurd.
Who wouldn't want a ride like that?
Even knowing I'm going to get picked apart or bashed, it was an attempt to answer the OP's question.
I'm not suggesting anything that opposes any linked or referenced builds.

[I'm suggesting that the last 300 rpm near or past peak hp is negligible on a huge car with a tame engine, same with the horrid unpleasantness of a wild race cam (lol) ONLY below the converter speed. Midrange was suggested, 110* enhances that.]

[Edited. My apologies for getting sucked in]