rkk69olds

Trying to figure out if I should have expected my build to produce more HP and Torque than it did. See attached Chassis Dyno print out and please offer advice as to whether my expectations were too high. Was shooting for at least 300 HP and 400 lbs at the wheels....

1969 Cutlass
355
Forged 10.3:1 advertised compression pistons
#5 heads completely overhauled with SS valves and HP springs, etc...unported and standard size valves
Edlebrock performer RPM cam, lifters and intake
Mondello roller tip rocker arms and pushrods
Holley 670 street avenger out of the box
Mallory Unilite with MSD 8MM wires and autolite 85s
RobbMc 550 HP fuel pump
TH350 with transgo shift kit and B&M Tork Master 2400 stall
3.42 gears
225/75R15 tires

At the time of the run all components including trans and rear had 90 miles on them.

Think my biggest mistake was not porting and putting in bigger valves, but would like to know your thoughts.

Summary performance

HP - 237.61 at 5,200 RPM
TQ - 269.17 at 4,000 RPM

Warhead

You did not go wrong, you're not done yet, just need to work on the tune.
Advance curve, jetting, carb spacer, larger carb.
Did you block the heat risers in the heads?
I did not see your exhaust system either.
Those are good numbers for starters, at the wheels.
Jim

Run to Rund

You probably lose 20% going from flywheel to rear wheel figures. Porting would help a little, a little more cam would help if the rest of your setup will work at higher rpm.
Also, as pointed out above, tune up helps. Richen the carb jets and see if that helps, try different timing curves.

Beob

I agree fine tuning is a must, also are the rockers adjustable? If so re-check that as well. Can you do a compression test? 300hp+ should be no problem

captjim

Carb is too small. I had a 670 Street Avenger on my mild 9 to 1 355. I ended up 5 sizes higher on jets and a 50 cc pump. Olds engines like big carbs, IMO. see if you can borrow a 750/780. A better cam would probably help with TQ and maybe bring it in lower.

rkk69olds

Thanks for the replies.

I made a rookie mistake and did not fill the heat risers
Exhaust is flow tech ceramic headers with 2.5 pipes and flow masters
Total timing is 36 degrees.
Valve train is fully adjustable

What is the best way to check for the ideal timing curve?

I think 670comes with 65 primary and 71 secondary . Air fuel ratio looked pretty good at just below 14. What would you suggest?

I thought about a bigger cam, but did not want to tear into it soon. If I do that I will take the opportunity and put in bigger valves and do some porting.

captjim

Did you degree the cam? I would try and borrow a larger carb. I ended up getting best ET at 68/74 on a milder 355.

36 might be a tad high for that Cr/cam combo.

captjim

Carb calculators work on paper, not in the real world. Internet engine builders use them. Every one I have seen recommends a carb that is too small.

The SBO Performer RPM cam is 214/224, you listed the BBO RPM cam.

You don't "try everything under the sun" you tune and tweak using a systematic approach, not tossing parts at it.

71 Cutlass

I assume you are looking for a race car and not a street car since you were expecting 400 HP at the rear wheels. In such a case, the entire engine will have to be made into one which virtually has no resemblance whatsoever to the original one. As was suggested above, you'll need bigger everything.

If you are actually looking for a streetable vehicle, then everything (size of components) is fine. Perhaps a little tweaking will get you a little more HP, but those number are about right.

captjim

Are you EVER going to make an accurate post? Ever? He did NOT state 400 RWHP. He stated 300 HP and 400 LBS (that means torque). That means 375 HP +/- at the crank, that is certainly do-able and streetable, though I do not think he can get there with stock heads. 400 RWTQ is asking a lot out of a 355, 350 is more reasonable.

71 Cutlass

Simply misread his post. As for accurate, you have NO idea if your carb suggestion is valid. He even said the dyno showed air/fuel ratio looked fine. As for the cam, I correctly posted what Edelbrock has on their website:Performer cam 7112 is listed for 350-403. Anyone can look it up to verify. If Edelbrock mistakenly put up any wrong numbers blame them. Also, you missed the entire point behind my original post. "Everything under the sun" refers to all the numerous and conflicting suggestions people receive on these boards, and there is no way to know whose advice is the "true fix." As I stated, and it is irrefutable, one person says try "this" another says , "That's a ridiculous suggestion, instead try this." Then someone else says, you're both wrong, try this." Thus my comment that a person is virtually told to try "Everything under the sun. " You refer to a "Systematic approach" and say don't try "everything" but you never define and never post for anyone what your "perfect" systematic plan is. It's ridiculous. Of course it's obvious you believe your suggestions are the only ones that will work

RAMBOW

LOL!!!

nah, remember you are talking to the guy who said its not possible to make 350hp out of an olds 350 w/o it being a full on race motor.

captjim

exactly!! Lol

71 Cutlass

I stand by that comment. That post referred to a 350 that had 180 HP and someone was looking to make 350-400 HP out of that 350 motor. If you don't think that motor has to be totally re-done to get that much more HP, making it a motor for racing verses a daily driver then best of luck in your future build ups. Also, others on that thread agreed with my position, thus your posts here are simply proving my point..."Everything under the sun" is suggested to people asking questions on these threads.

captjim

Keep digging the hole, it's getting deeper.

If you INCREASE the cfm of a carb, you INCREASE BOTH the air and fuel volume. Ratio stays the same, but more air + more fuel means more power, if the engine can handle it. I posted real-world actual experience using the SAME carb on the SAME Olds 355. I think that my advice is pertinent. I did not use an online calculator or Desk-top Dyno to give advice or experiences.

I am giving "systematic" advice. There is no "perfect" plan. IMO, the carb it too small (so does Warhead) I and suggested he try a larger one before any other changes. I also suggested he back off the timing a touch.

71 Cutlass

Not debating your experience. Again, you missed the point..the hole is getting deeper. Your advice, which is fine, is coupled with other advice that does not agree. Read all of your threads and see for yourself how many people have disagreed with your advice during your time on this board. Not saying your advice is right or wrong, just pointing out all the differing suggestions "Under the sun." Glad you finally admitted there is no "perfect" plan, when comparing "Everything under the sun", that simply proves my whole point. Now we agree. Simple

Rickman48

I disagree with "porting will help a little"! IT'LL HELP A LOT!!
By installing larger valves, and not doing the bowls, that destroys any benefit of the larger valves!!
Think of an inverted milk jug - a larger cap won't help if you don't increase the neck!!
Will even destroy what flow there is!
By match porting the ports, cleaning up the bowls and back cutting the valves, I could see another 10 - 20% HP and torque gain, with the proper jetting and timing curve!
I, too, would try a larger carb!

380 Racer

Sorry 71 but Jim is one of the most methodical, thorough and accurate guys I know. He's proven himself by making videos of degreeing in a cam, plus track and street testing. He knows his **** plain and simple. Play E.F. Hutton when he speaks........you should listen!

And from my past expierences, I agree, go with a bigger carb.

71 Cutlass

Guess that means everyone whose disagreed with him is wrong??? I believe plenty of others have just as much to contribute, including those who have differed with him. If you have confidence in him, keep it, not trying to take that away from you, but no one on internet boards holds all the trumph cards for every problem. Einstein himself made mistakes and publically stated he was constantly learning. It's true for us all.

gearheads78

You can pick up a little here and a little there with tweaking and turning but you are never going to make any real gains without head work. Using stock unported and valved heads is putting a cork in the system. I made the same mistake on my first performance build. It was a 9.7 383 SBC with 882 stock heads. It was a mild street / strip car I ran at the local 1/8 mile tracks. I fought the thing for 6 months. Different carbs, timing , jets , converter, gears. The thing just would not run faster than consistant 8.4x's with a best of low 8.3x

I finally broke down and put a set of Iron Eagle 200cc heads with 2.05 1.60 valves. With no changes in tuning my very first pass was in 7.8x's and it only went down from there.

You can't just call up summit and order some Darts for an Olds motor but spending some money on a good head guy to install big valves and a decent port job with make it a different motor.

RAMBOW

Sorry to take this off tangent (but i'm going to anyway)

Which would you perfer to start with?
Small valve C heads, add large valves & port work
or
Big Valve E heads, and just do port work.

I have read the Olds Faq, and it seems to indicate that small valve heads are a better starting point to make into performance heads- converting to big valves & doing port work vs starting with factory big valve heads and doing port work.

Does that question make any sense?

71 Cutlass

What Gearhead said is what everyone I spoke with told me before I did my rebuild... this includes Dick Miller and John Stopla. They both seemed concerned that without head work, I would not be happy with the outcome I wanted. RAMBOW, acccording to these two guys, your question makes plenty of sense, because they told me to use the heads that came on my 71 350 and have them ported with big block valves installed (2.00 and 1.625). I asked Joe P. about it several years ago and he actually said the same thing...to put the big block valves on my current Olds heads. It seemed that no one disagreed with the idea to use the small block heads, and just have porting done and use the bigger valves. Not sure what the absolute best way to go is,( head choice: Olds vs another brand) but it does seem that everyone is in agreement on one thing: the restrictive nature of the heads in stock form will not allow a car to achieve its full potential.

captjim

I am wrong as often as the next guy and disagree with guys I like a lot. I am also a hard-headed know-it-all sometimes. The difference is, I use data and experiences from real life. Too many guys on these forums repeat second-hand info, incorrect info gleaned from the internet, and give advice based on Decktop Dyno and online calculators. You "mis-read" and "mis-type" a LOT.

You have written a lot of words in this post, yet not given a single piece of practical advice based on personal experience.

71 Cutlass

Guess you missed my post right above yours regarding head work. Apparently you miss "a lot" as well.

Run to Rund

OK, wait a minute. If you lose 20% power to the wheels through the drivetrain and accessories, you have 296 HP now, gross, at the flywheel. With a cam smaller than the W31, and the smaller valves, you are right on target vs. the W31 with 2" intake valves, 232 deg. at .050" cam that was rated gross at 325 HP.

You put in some speed stuff but nothing that would impact HP very much compared to what Olds did 40 years ago. the carb is smaller, not a big deal with your mild setup, but the smog jetting it probably has doesn't help any. Your ignition and fuel pump are good, but don't expect them to add HP with a mild 350.

In summary, your engine is about where it should be, for HP. 300 at the wheels would mean about 375 gross, and you did nothing that should give a big increase over the W31 setup into which Olds put a lot of thought.

Run to Rund

By the way, Jim and others gave some good advice above. A 750 cfm Quadrajet would work well, but you have already bought something smaller and it is cheaper to try to get it to work its best. I have been happy with 850 cfm (actually calculates to 847) with Tri Carbs on a 400. However, I use a LOT more cam than you are using (and 4.57 gears), at least 244 deg. at .050; you could get 20-30 HP easily out of a larger street hydraulic, like the Comp XE274H or the almost-to-big XE 284H. But, do you remember that one of the magazines tested a W31 and it came from the factory for use in magazine acceleration testing with 4.66 gears? You already have all the cam you should use for mild 3.42 gears. If you really want to get 375 HP gross, you need the rest of the combination to fit, like looser converter and 4.10 gears or thereabouts.

captjim

No, I did not miss it, it was just you repeating what other guys said, not any real experience. Also, not sure what advice you are giving? Suggesting that he pulls the heads and do $1000 worth of port and valve work really doesn't help him out much. We all agree that much HP will be very tough to reach with stock heads.

rkk69olds, just to be clear, what cam and chain are in it and did you degree it?

MN71W30

It looks to me like he achived his goals with the chassis dyno. An engine dyno is an ideal situation with controlled water temps and no accessories spinning on the motor. Could it be a little more than a 20% loss?
I would like to know if the owner is happy with the way it runs. I got quite a few friends with alot of hp under the hood of their old car but drive like old women. So if you aren't at the track, who cares if it 300 or 350? If it runs and drives nicly and will lay down some rubber, try to be happy with it.
When I was a kid and wanted my cars faster my Dad always said "Theirs always a faster gun"
It sounds like a great running 350 to me.

rkk69olds

Appreciate all the input - lots of great opinions and experience on this site. I thought I had done a pretty decent job planning this build (all components working well together), but there is always room for improvement. I had end numbers in my head, but again not sure how realistic they were. Either way I am pretty happy with the way the car runs. The constraint now for me is $$$ as I have sunk about $9K in the entire drive train (no comments please ) and need to be smarter about any more upgrades if you will.

captjim - cam is a performer RPM and chain is a comp cams 3113 if I remember correctly. Cam was degreed in by the machine shop as I did not have experience or tooling.

Will try a larger carb and work with the timing. I will have to go off feel at this point as each trip to the dyno costs $300....

Have been toying with going to HS full roller rockers in place of my mondello roller tip ones - any benefit?

captjim

$300!!!! Holy crap!. $75/3 pulls here, yikes.

When you say "performer RPM" is it the 214/224 or 224/234 cam?

As long as it was degreed, the chain doesn't matter, so you are good

If you are happy with the performance and it is fun to drive, forget the "numbers".

No need for the rockers, IMO not a cost effective upgrade.

What are you running for fuel?

Borrow a 750 Holley, drop the timing down to 32-34, see what happens.

Warhead

I can Understand you're not anxious to pull the fresh heads.

If you do end up going this way, have another set done the way you want, and do a weekend swap to lessen the vehicle's downtime. JMO

Otherwise, Don't look at everything under the sun, just look at everything under the hood.

There are dozens of things that sap power from the engine, the things listed above are but a few. Here are a few more:
Small dia crank pulleys can free up 5 hp or more
What kind of cooling fan do you have?
Carcraft magazine's test found cooling fans rob as much as 45 HP
You can change fans, and get 20-25 back without affecting your cooling.
Most engine dyno guys find 5-10 hp with a carb spacer
You can gain 7-10 HP by blocking the heat risers under the manifold.
It cools the manifold and lessens pressures to other exh ports.
Isolate all heat from carburetor, and fuel system. Cool dense fuel and air make more power than if heated up. Cool cans, and ram air. Separator plate under the carb.

These are surefire, Guaranteed ways of making more power, that works on any internal combustion engine.

You don't have to crack the heads off, to reach your goals. The rockers may gain you 5 hp due to more accurate 1.6 ratio, but price for HP gained is a bit expensive to me.
That's how I see it.
Jim

captjim

^^^^^^^ Good post, I noticed the difference when I ditched the mechanical fan. I will disagree with the cool can, IMO not worth the hassle, but cold air, DEFINITELY. My first run I went 14.8 and whittled it down to 13.9 with tuning and attention to detail.

71 Cutlass

rkk69olds,
$$ for head porting is not $1000, as stated above but half that, so if you decide to go that route, know the cost is much lower. Speaking of price, a dyno run for $300??? Price here is the same as Jim's neighborhood, 3 pulls for $75. Perhaps there's another place you could try?? As for now, and I mentioned this above and then Rund to Rund said it as well, your numbers are about where they should be at this time, given the components you have.

captjim

Really? You can get me ported heads with new valves and a quality valve job for $500? I'll take 2 sets. I suppose you could try and port them and not put larger valves in. That is difficult to do without nicking a seat. These are prices our here,
Port work, $300
multi-angle race valve job $325
Set of 16 valves, $175
exhaust seats (if needed) $100
Surfacing, valve guides, other machining can easily put the cost at a grand.

71 Cutlass

Ahh, referring to labor cost Jim...your post said $1000 for port/valve WORK, nothing about parts. After all, when someone posts that a dyno run is $300, then someone else posts port work is $1000. it garners attention. Finally, as for real experience with porting you're clueless as to my involvement with my heads being done or the results that were gained from having them done, yet you claimed to know... foolish.

Prices here:
Pocket porting, 3 angle valve job, tear dropping valve guides, etc. =$500.00 (labor)

Rickman48

I was thinking the same as '71 - way too much$$!
When I was doing it in the late '70's, it was about $250!!
You're part of the way there, with the big vaves installed already!
Shoud be 'friendlier' on price, to a repeat customer, too!

captjim

This is NOT the late 70s and he did NOT have the larger valves installed, that cost was reflected in my price. Are you going to go to all that trouble and not install larger valves?

Now that I think about it, Jim (Warhead) has a good idea. Get new cores, do them right, install them with little down time, then sell the stock but fresh heads and he would be way ahead of the game.

captjim

I do not claim to know anything about you, other than the fact that your posts reflect your lack of practical experience. You quote Olds FAQ, Desk-top Dyno, internet data, calculators, and you repeat things others guys say. Oh yeah, and "mis-type" "mis-read" and add 100 ft/lbs when it is convenient.

I posted this,
https://classicoldsmobile.com/forums...arts-list.html
a comprehensive cost to a stout 355. Several EXPERIENCED guys said that I was too low on the head work.

Dave Siltman

Are 71Cutlass and CaptJim ready for the boxing gloves yet? I'd say listen to the "old-timers" and try what they are saying. G.M. made well over 300 HP forty years ago with a W31 with cam technology that is outdated by todays standards. I say try a GOOD Q-jet, and a GOOD clutch fan (can you say W31) and start some FINE tuning. Don't change more than one thing at a time. I am an "OLD" drag racer and know how to "HUNT FOR TENTHS". Check out what the old-time N.H.R.A. stockers did and you'll see what I mean. Finding hidden horesepower is an art---listen to the old-timers, they've probably tried more ideas than you can think of. Cubic dollars don't make horsepower---a good combination does---and the good combination ia a result of hard work and trial and error. Don't give up easily. 10hp here, 5hp there, a "little" change here and there will yield satisfying results. Your dyno sheet should now be used as a baseline from which to start. Looking back, working the heads a little and installing bigger valves would've helped but I don't think you have found the optimum potential in your present combination.

71 Cutlass

Again, you are Clueless as to my experience with the head work done on my car. Foolish X2. I had to quote you your own post. And just FYI, your opinion does not = factual statements.

Good post above by Dave Siltman. Just read the Hemmings Muscle Machines article from last month on the W-31, and he's dead on about the power. That entire line of thinking that Dave referred to was the impetus behing my W-31 build up.