KDW

Hello gents
I need some help or to be pointed in the right direction on a motor build?
This is what I have: bone stock 1972 455 big Block, Ga heads, fresh th400 Trans, 308 posi. With headers 2.5 exhaust and flow master
Motor will be in a 72 Cutlass Supreme original BB car.
What I’m looking for is some more cam Sound and HP! I’ve been told to just have my heads worked with bigger springs and put a 270 cam, 30 over bore and leave it alone. I’ve toyed with the ideal of purchasing aluminum head for performance but don’t know how much more HP I will gain over stock heads. I still want to run pump gas. Is this possible? and if so how much HP would i gain? my guess is that my exsiting motor when fresh is only producing about 250 HP. I want to have that nice crisp sound at a light without sacrificing drive ability and having to put a large stall converter in the car. Do I run flat top or dome pistons, do I change manifold etc
I would love to hear what you Big Block guys are doing or parts/ heads you may have available.
Thanks in advance

ah64pilot

First thing is first, what's your budget?

KDW

1500 to 2000 unless I can find some deals on eBay or the local trader

ah64pilot

Good to know. So what you have is a low compression 455 with mediocre heads. If you want any kind of power out of it you are going to need to bump your budget or stick to the top end (intake manifold, carb, head work). Unfortunately with such low compression you are spinning your wheels unless you can get the funds to do the WHOLE engine and do it right.

Here are two examples: I have $10K in my silver car engine. I have $4000 in my convertible engine. The silver car makes 500 Hp / 550 Tq. The convertible is a basic stock rebuild reusing "E" heads. Neither of those builds are in the $1-$2K range.

Here's a good read on what it cost to rebuild an engine: https://classicoldsmobile.com/forums...arts-list.html

KDW

Ok thanks for the read. That's what I was looking for. I had a local machine shop tell me I could build something my for about 2000. He never mention anything about line bore, decking etc

ah64pilot

When they quoted that they were probably just talking about the short block. You would still need heads or head work and a good intake etc.

What is your goal for the car? Just to sound good? Or do you want it to perform as well?

Dave Siltman

Ah64 is right! If you can get by for twice your allotted budget you will be doing something. If "cruising" is yout intention, I'd say just freshen up what you have and take some time tweaking and fine tuning. A good (one that really knows Oldsmobiles or RACE motors) machinist will tell you up front what it will cost to make some horsepower and have the thing stay together. Now you know what a sacrifice us Olds guys are REALLY making!!!
Listen to some of us here and take our advice----we (most of us) will guide you in the right direction. That engine you have, with a good, stock, somewhat blueprinted build should yield enough good street power after some fine tuning. Also, to get some grunt on the street, put some healthy gears and a stout tranny behind it. I think you will be surprised what you can achieve with those changes.
Don't blow your checkbook on just the engine!!! Ask Ah64, or 580, or me, you need MORE that just the HEART!!! CutlassFI has some great advice on builds---seems to be very in tune with today's technology. Myself, I am lost in the '70s and make power with old stuff---these other guys are lightyears ahead of me! Good luck and stay focused and by all means LISTEN TO THE GUYS WHO HAVE BEEN THERE!!!

KDW

My goal for the car is a little more performance and some sound. I love that crispy American muscle sound. Is this possible with a 30 over bore get more hp? working stock heads a bit (having the machined to take a larger spring for cam lift) new intake, 600 or 750 carb etc in other words a good almost stock build to get some sound.

If you have a formula that would work I’m all ears! Also I understand about the budget may need to be increased

citcapp

Just boring 30 over doesn't gain you anything without new up graded higher compression pistons such as the Keith Black IC886, plus reconditioned rods new bearings, more aggressive cam and some head work. I am leaving out the machine work. Check out the build thread that Ah64pilot gave you a link to.

Also Intake and carb work will be required to make it all work together.

Yes you can save money by collecting parts off of other sites. That's how I built both of my engines buying out other builds where the people either changed their minds or just gave up on their builds

ah64pilot

Here's a formula for a good sounding street engine that performs as well...but it's not in the $1-2K range.

455 - over as little as you need (.030", .040", etc)
TRW forged pistons or for not much more IC886's
good machine work on bottom end
balanced
Stock heads, valve job, seats, springs seals
Comp Cams roller tip rockers (adjustable, steel)
Edelbrock performer intake
Edelbrock 750 carb
Engle 20-22 cam (.496/.512 lift, 226/230 @ .050" duration, 110 LSA
Either stock manifolds and 2 1/4- 2 1/2" pipe or headers w/ 3" pipes
HEI or MSD distributor

Again, this is a strong runner but not a race engine. However, it's still going to cost you somewhere in the $4500 range to do it right.

KDW

Ah64pilot thanks

That engine build looks nice and something I won't go broke doing. On the heads completely stock?

ah64pilot

Yes, I just had the seats changed, maybe new guides I can't remember, and put new valve springs and seals on them. Your machinist can check them out and replace what's needed.

KDW

I know recommend eagle cam, what are your thoughts on comp thumper cams? Also this is just a thought procom aluminum heads?

ah64pilot

I have never run a thumpr but from what I've heard they are all bark and no bite. That Engle cam I suggested has a nice rumble / lope to it. I will be breaking in my convertible engine in a couple of days...I'll take a video so you can hear what it sounds like.

As far as procomp heads, I can't / won't make a statement on them. I don't have any experience with them and to me, the few hundred more to get Edelbrock's is worth it. JMO.

KDW

KDW

To hear your car would be fantastic! You guys have be a big help! This hobby is no joke. Lot of money and time. Please hit me video of your convertable would love to hear it .

Thanks

ah64pilot

Will do when I get the engine in...probably in 2 days

KDW

Hello did you get your motor running?

KDW

Hello did you get your motor running?

ah64pilot

I sure did...



Just for laughs, here's one of the silver car:

trucker442

Kdw, for some good info (imo) on olds engine building, check out a book written by bill trovato called "how to build max-performance oldsmobile v-8's" i purchased my book on ebay. This book will guide you on important and unimportant items. I enjoyed this book as i need all the help i can get for my 455 to. Good luck with your build!!!!!