Ctott70

Hello all,

I have an 70 Olds 350 with 7a heads that is in need of rebuilding. I wanted to beef it up from stock but am having trouble deciding on what to do. I wanted originally to get the RPM performer BBO Heads and the matching Intake Manifold but have been reading that they are a waste of money. Any suggestions? Are the 7a heads any good or should I try to find better ones?

Thanks in advance for any help that you can provide.

cutlassefi

What are your goals, budget, what's it going in? Do you want to keep it more original or you don't care.

Lots of questions to answer.

Ctott70

I would like to reach somewhere around 320-350hp. It is a 1970 Cutlass Sport Coupe that will strictly be a weekend driver. Not planning on taking to the track, strictly street use. No real budget constraints, but if I had to give an amount I would say $2000-$2500 would be okay. I would like to keep it as original as possible but that is not major priority. I plan on putting a 3.42 rear end in it, it currently has a 3.08.

I hope this info helps.

Thanks again.

Dave Siltman

Get a set of #5 or #6 heads and a GOOD stock rebuild with @ 9.5-10.00: 1 compression should yield you somewhwere in the neighborhood of 300hp. The budget is within reach if you don't get crazy. I'd suggest hardened seats in the heads and a newer profile cam.

cutlassefi

I agree somewhat.
Install 2.00 intakes, RPM manifold, 700cfm ish carb, shoot for 9.5:1 compression, fill the crossovers and weld the dividers, balance, headers, you're there.

Cams, don't use a generic, 214/224, 224/234 etc and don't use a Comp Xtreme, VooDoo etc, not enough off the seat time for stock heads.

Jmo.

Ctott70

Thanks for the info. So I am assuming that it is not worth it to have my 7a heads modified? Any suggestions on rods and pistons? I've heard you could put sbc 6.200" rods with a 2.100" crank diameter. After thinking about it a little more I figure my budget to be more around $3000. Don't know if that changes any of your suggestions but I was not including the Machine Shop work for the block. I am also not including the cost of stock replacement parts and/or dress up parts.

Thanks again.

380 Racer

There is nothing wrong with the 7a heads, they are about like all the others in that era. If you use Chevy style rods, you will have to use a Chevy style piston and use a .927 piston pin. Somebody else will have to help you find the right off the shelf piston that will work, as far as pin heigth, bores that are available, deck heigths, rings and etc. I have only used custom.

captjim

Stock Olds p/h is 1.615" and a 6" rod. So by going to a 400 SBC piston with a 1.425" p/h and a 6.2" rod, you get there without having to mill the block, you will be very close to zero deck. You will have to bore to 4.125", the 400 SBC bore and cut the crank .025 down to the 2.100" SBC size (extra expense), but that cost is offset by the ability to use off-the-shelf parts. The main issue with achieving an honest 350 HP is the cylinder heads. Spend a little extra, do them right, choose a good cam and you will be happy with the performance.

Like Nick stated, no reason not to use the 7a heads that you have, they already have hardened seats (if re-usable).

Ctott70

Thanks for all the help everyone. This is my first Olds, as if you couldn't tell, and I need all the information I can get. I usually deal with Fords but I have always wanted a 68-72 Cutlass. There is a good story behind this Cutlass too...It used to be my cousins and several years ago he got clocked doing a buck thirty by a cop headed the opposite way. My uncle was driving the car the next day and got pulled over by the same cop who recognized the vehicle. The cop told my uncle about the previous incident and my uncle parked the car for good...or at least until I showed interest. Now I don't care so much about top end but I would like to be pretty quick off the line. From what I read the Rockets are beasts and I am really excited about this build. I welcome any and all suggestions, not only in rebuilding the engine but also good places to get resto parts...i.e. Body panels, glass, interiors...etc. Like I stated previously budget is not as much of a concern for me as doing it right is.

Thanks again everyone.

Aceshigh

Yep.....read this. Edelbrock performance package 397hp with #5 or #7a heads.
Obviously they've had work done though.

https://classicoldsmobile.com/forums/229279-post9.html

I wish I knew exactly what was in my Rocket 350 for cam, etc.
But it's putting 425ft lbs of torque down
I can't burn rubber with the new 3.73 posi , Nitto 555R rubber, and 285/40/18's
but it launches FAST from a dig with all that traction

cutlassefi

I talked to Edelbrock about that claim some years ago, they told me it had "extensive" bowl work on the heads.

olmace

I have a 310 hp 70 350 you can have for $400. Greg nuolmace@aol.com

71 Cutlass

I found out the hard way on that false advertisement years ago. Used the parts Edelbrock said they used and was NOWHERE NEAR 397 hp on the dyno. Later I find out they basically re-did the motor in order to reach those numbers. Of course Edelbrock never said, "By the way, takes other engine work to reach that number." I also believe more than bowl work was done on that car...there had to be. My heads have had massive work done to them, including big block valves installed and I don't make 397 hp, so bowl work alone won't get you to 400 hp on a 350.
That's my experience with "The Power Package" and 400 hp.

Aceshigh

So you matched all those components up and couldn't get 397hp ???

What did you end up with ??

I have no doubt overstated claims are made to sell a product.

71 Cutlass

If my memory serves me correctly rear wheel hp was around 218-220. I remember thinking how ridiculous the number was when Edelbrock had said the "tested" power package would yield 400 hp. Then the waste of $$ started to enter my mind and I thought, "I should have called a Mondello, Dick Miller, Dave Smith, or someone like that instead of buying into the hype from someone else." All this was around 7-8 years ago.

For clarity:The build up I have now with head work, big block valves, flat top pistons,etc. was not done when the "Power package" was installed. I have no dyno numbers as of yet on my current build up.

Aceshigh

oh.....wow. That's roughly 275hp after the 20% drivetrain loss for an Automatic.
Of course it's not a perfect science on the % of loss with a loose trans or TC.

Did you use EVERYTHING listed for the power package??
Including the compression and 1.995 valves and 1.6xx ??

That's a huuuuuuge difference of close to 125hp difference in their claims.
Something can't be right.

71 Cutlass

Compression and valves were NEVER mentioned in the power package. Are they NOW saying "By the way you need all these extra parts or it won't work"? If so, it is many years too late for those of us who tried it years ago.

captjim

We have had this discussion before,
https://classicoldsmobile.com/forums...y-rebuild.html

You put those pieces on an engine with 8.5 to 1 Cr, STOCK heads, and STOCK exhaust manifolds, not even remotely fair to compare.

71 Cutlass

Edelbrock's presentation of that 350 power package never stated that the gains were made from anything other than a stock motor. So I am comparing nothing, but simply stating what Edelbrock presented. That's not unfair. What is unfair is the results I got from following this so-callaed 400 hp set up that was a waste of $$$. Maybe Edelbrock has altered their presentation of what 350 motor (and all of the changes made to it that totally changed it from a stock set up) was actually used to get to 400 hp... I don't know, and of course could care less at this point. I'm a big fan of Edelbrock products, always have been, but the 350 Olds 400 hp (just add a few parts) was nothing but nonsense.

geckonz08

Glad you mentioned it . We all need to hear and beware.Advertising from ambiguous to down right lies is everywhere and dissatisfied pun ters do ua all a favour by bringing it to our attention .
mike

olds 307 and 403

The RPM heads aren't necessary for low 300 hp goals. That being said, how many SBO heads flow 275 cfm intake? Have a modern chamber and light weight? Even the old Edelbrock heads were worth a good 50 hp over 455 heads. They have 190cc runners which is not big for a hot 350. Edelbrock did all the improvements needed on these heads in my book, except the mechanical fuel pump issue. They are available and a quality casting. Not so for the other heads.

380 Racer

Sorry but I have yet to see a 50 Hp increase over a C head. The modern chamber isn't setting the world on fire either. I really like my Rocket Racing heads, they make my SB really come to life with 2.2HP per intake cfm. Just wait till they are actually ported .

Aceshigh

I would be pissed off myself.
I'm glad you posted this up. I would have just assumed it was buying their
components got you the 397hp. Talk about false advertising scams.

Samething with Desktop Dyno bro......
I have the 2003 edition and for a SBO 350 it has all the W-31 #6 head setup info.
It doesn't have any flow characteristics for regular 350 heads. So it's very deceiving.
I had to dig and dig to find true SBO 350 flow #'s for #6 heads. It does make a difference too.

Agreed. I'm at roughly 300hp / 410ft lbs in my 1970 350 with #6 heads, RPM intake, 750 Eddy carb.
I have no idea what cam , valves, springs, pistons, etc though.

It was built down in North Carolina and I just had it dyno'd out.

michael hilsabeck

didnt oldsmoble come out stock 310hp?

Ctott70

Can anyone give an estimate about how much it would cost to have the larger valves installed into my 7a heads? I was thinking about just boring my 350 block .030" over, get some cast flat top pistons, beef up the heads (port and polish, install larger valves), use a 750-830cfm carb, and headers...How much HP do you think this will get with the proper cam?

Thanks,
Chad

michael hilsabeck

i am having my #6 heads done but i have stock valve time they are done 500$ . i am rebuilding the motor 350 1970 with flat heads 30 over. time it done i will have 1000@ block work. and everything elese 2500 it not chep for a olds

Aceshigh

1970 350 options

1970 2BBL 250@4400 355@2600
1970 4BBL 310@4800 390@3200
1970 4BBL 325@5400 360@3600 W-31

I was wrong, the W-31 had 325hp , so I guess the other 4BBL versions were 310hp.

71 Cutlass

Just remember that those HP numbers are taken "the old fashioned way." I believed it was called brake horsepower. Today's numbers are net HP, so when you hear of a 2010 Camaro with 350 HP or whatever, that's entirely different than a pre-1972 HP number of 350 HP. Case in point, my 1971 motor was rated at 260 HP. In 1972, the same motor in a 1972 Cutlass was rated (using the new standard) at 180 HP. So keep that in mind when figuring what the actual numbers a 1970 motor would be by today's HP standards, otherwise when you dyno your new built up motor you'll wonder why the HP number doesn't seem high enough.

Aceshigh

Correct

Yet ANOTHER big reason you can't compare 300hp in 1970 to 300hp of today


Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower (bhp), frequently referred to as SAE gross horsepower, because it was measured in accord with the protocols defined in SAE standards J245 and J1995. As with other brake horsepower test protocols, SAE gross hp was measured using a stock test engine, generally running with few belt-driven accessories and sometimes fitted with long tube (test headers) in lieu of the OEM exhaust manifolds. The atmospheric correction standards for barometric pressure, humidity and temperature for testing were relatively idealistic.

Ctott70

So basically if I got this right, my 70 Cutlass 2Bbl 350 was advertised as 260HP but was actually on 180HP? So by adding a 4Bbl carb, Port and Polishing the heads, boring 0.030" over, using flat top cast pistons, a well matched cam, and roller rockers..I might get my 350 to the "NET" 260HP-300HP mark?

cutlassefi

Essentially that's correct but you don't need to port and polish the heads to attain 300hp.

By the way, Champion head services in Palm Coast Fl. charges about $300.00 to do a full 5 angle valve job, check spring heights and cut for larger valves, pretty fair in my book and their work is top notch.

captjim

^^^^^^^^^^^^ More than fair, IMO^^^^^^^^^^^^

Nobody gets more aggravated that I do about "numbers". Don't confuse peak HP numbers on a dyno with actual performance. HP is just a mythical, theoretical number, it has never been measured on a modern V8 engine. It is a function of torque and rpm. Since Olds engines generally don't rev high (they don't need to) they don't make big HP numbers. 455s made like 325, ever drive a well-tuned Cutlass with a 455? Kinda fun. A broad torque curve is much more important.
FWIW, the mild 355 in my clunker G-body wagon made 262 RWHP and ran 13.9.
Read this if you want to,
http://www.oldspower.com/vb/showthre...ight=overrated

380 Racer

Jim, I agree with you on many things, but not your dyno opinion. The dyno is another tool and indicator to help build and use the engine to it's fullest. My motor uses the peak torque at the peak of my converter and has the car in motion. That's 589 ft lbs @ 5400 and then tapers down but then is just maintaining the motion and making HP. The dyno showed me what I could expect from ideal weather conditions and at sea level. We also tuned the motor and broke it in before my car ever saw it.

The first time out and after doing the weather & altitude corrections it ran exactly what we thought it would. I really doubt you could do that without a dyno. In the end both torque and horsepower are a measurement of work. You plain cannot have one without the other in a car.

Aceshigh

Taken from your thread where alot of people disagree with your theory.

I agree with him.
Stock 1970 442 with the 455 ran a 14.2ET in the 1/4 on factory tires.
Now if you added drag radials to it , I'm sure it would do better.

But I disagree with your theory on HP being negligible because of these reasons as well.
I've seen plenty of tuners smoke muscle cars that think they're fast because they make a good exhaust note.
Most don't make anywhere NEAR the torque that the 455 does.
But the 455 can't rev and make big HP in stock trim.

Putting the power to the ground is your #1 problem with all that torque on stock rim sized tires.

380 Racer

By the way, my adjustment calculations were based off of the horsepower not the torque.

On another note you can't go heads up against old horsepower ratings things were just plain *** done differently back then.

Also it is kinda the same because track testing cars by different magazines on different tracks had varying results. Just like the internet of today.

captjim

You can disagree, too, I never said I was right, just my opinion. Also, coming from a guy who adds 100 ft/lbs of torque to his builds, I really don't respect or pay much attention to what you say. Yeah, you said "mis-type" but you mis-typed every single time. Only when I called you on it did you change it. The mythical 350 with 425 RW torque...................You are also very big on re-posting faulty OldsFAQ data, using desk-top dyno to back up statements, and using innacurate math. All of this just shows your lack of "real-world" practical experience. The inrternet is fine, but we race cars, not dynos (or desk-top dynos).

Nick, I respect your opinion and we just disagree. I think a dyno is a decent tuning tool, but not the end-all. The problem is that the dyno controls engine acceleration, which by definition then controls HP. Not to mention "corrections". Also, you are talking serious, high HP race cars, not drivers. Situations where you launch at 5500 rpm. Certainly in that application, HP is a factor. But again, all HP is is the ability to make torque at a high rpm, in other words to breathe.

As to dynos, the fact is indisputable, dynos do NOT measure horsepower. They are incapable of doing so. They measure torque then use a mathematical formula to ESTIMATE horsepower. Control the rate of acceleration, control the results. And Nick, witth your experience you know that engines accelerate differently in a car than they do on a dyno.

Aceshigh

1 post typo.....whatever.

380 Racer

Yes Jim I respect you, your thoughts and accomplishments. Aceshigh included.

bkeese

I decided to google Rocket Racing to see what you were talking about. I see they claim the Worlds Fastest Olds 425 9" @ 9.48 in the 1/4 mile. I was talking last week to a neighbor that has an Olds 425 Cutlass that runs 9.5 on all motor. Unfortunately the car is sitting with flat tires and hasn't been run in recent years, his son is in love. I guess that is about the limit. Now I have an idea what it takes to run mid 9s on motor in a Cutlass.

80_cutlass

H615CP

So piston like the above part number. There exists a plethora of 400 sbc piston options. 5.7" rod, 5.5" rod, 6" rod. I am assuming the ones with the 5.7" ones, since they have the 1.425" p/h. But the stock rod is a 5.565", right?

Seems like an interesting thing to do....I've got a couple of 350s sitting around.

sb