350 Olds Build

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I am pretty close to pulling the trigger on a 350 Olds engine for my 87 Cutlass. I don't know the full details about it but the guy who helped build it claims that it has 10.1 compression, and is full of "good parts".

I am building my Cutlass to be a pro touring car that will mainly see street duty with an occasional day at the strip or road course. I have been reading as much info as I can about Olds motors and what their strengths and weaknesses are. I am more concerned about the low end torque numbers to make it a fun car to drive around town with the occasional blast at the track. I would like 400+ ft lbs of torque with comparable HP numbers if possible.

My question is, how do I get there and how much will it likely cost? I am in no particular hurry to build this motor and if it takes a few years, so be it. What parts do I "need" to get me there? Again, this isn't going to be pounded down the dragstrip weekend after weekend, turning 7,000 RPMs every blast. I am aware of the bottom end weaknesses of these motors and what needs to be done to strengthen them, but is that necessary on a street motor?

Thanks.

 

[bill]

This is a great article to get ya started....building the 350sbo to w-31 specs is a good way to make the power you are after and still have a streetable car.....http://442.com/tech/tech.html

 

[olds307 and 403]

A 76 or older 350 does not have a weak bottom end, 400 hp should be no problem. The 77 and later are a different story, late 70's 400 Pontiac's had a weaker bottom end too. You will need premium or better with 10 to 1 and iron heads. Procomp heads will out do all but heavily ported 350 heads, just mill to reach the desired compression.

 

[jetsetw31]

This is a great article to get ya started....building the 350sbo to w-31 specs is a good way to make the power you are after and still have a streetable car.....http://442.com/tech/tech.html

A 76 or older 350 does not have a weak bottom end, 400 hp should be no problem. The 77 and later are a different story, late 70's 400 Pontiac's had a weaker bottom end too. You will need premium or better with 10 to 1 and iron heads. Procomp heads will out do all but heavily ported 350 heads, just mill to reach the desired compression.

X2 all of it.
Plus what you want it to do requires you to know these details.
What year is that engine?
What heads are on it? (#'s 4, 5, and 6 are the best Heads you can work with, #7's and # 8's will do with good porting.)
What cam does it have?
And finally what are these good parts installed?
in my experience (Not my opinion), the factory cam from the early 70's can support 400 hp by having compression and/or the ability to breath.
I say "or" because my first cutlass was a 80k miles, '71 4 door w/ 350sbo, 8:1 compression, 1000 cfm Qjet, dual point distributer, open Hooker Super Comps headers, A power glide with a 6 cylinder torque converter, 3.23 gears, 90/10 shocks, and truck springs in the rear(It never squatted). This car would consistently pull the passenger front tire on launch. Unfortunately It never saw a track. But it won me about 600 bucks street racing it. With open exhaust, it idled relatively quiet. I broke 1 TH 350, 1 flex plate, and 3 power glides. After the 3rd powerglide my mom junked it when i was in the military. All i could get was the headers and the truck springs back. This was 1981- 83. I stomped on mildly cammed chavys with a stock olds. No one could ever tell me a olds 350 wasn't a sleeper motor.

So I say you have a chance at a very capable motor.
T

 

[DoubleV]

I am pretty close to pulling the trigger on a 350 Olds engine for my 87 Cutlass. I don't know the full details about it but the guy who helped build it claims that it has 10.1 compression, and is full of "good parts".

AFAIC, any 'rebuilt' engine with no receipes, no real details ( 'good parts' instead of knowing the exact parts ), and built by someone you don't know or trust, is worth little more than a core engine. People ALWAYS overestimate the compression ratio and then almost always overcam it ( and don't degree the cam to boot ). Lots of power in the heads but most do nothing but stock rebuilds on them without any improvements ( or do things wrong like hog out the ports ). Also can't trust the skill of the guy who built it either. People will also skimp on important things to save a buck too. Personally when I see a 'rebuilt' engine being sold for chump change, I run far away from that engine as I know it ain't what it's claimed as being. If it's fresh and hasn't even been fired, I run away faster!

Now I'm not saying this engine you're looking to buy is junk or the guy didn't perform a TRUE rebuild on it. It may be a great engine but don't be suprised if it doesn't perform the way you may expect it to. Do you want to take that chance?

IMO, a 403 would suit your needs better. It's like a big block in a small block package. You don't have to build it as radical as a 350 to meet your goals either. What sort of ET's are you looking to acheive? Much easier to give build advice with an ET/mph goal rather than HP/torque numbers because peak HP/torque numbers can be VERY misleading as to how the engine will actually perform.

 

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Thanks for all the input.

As far as the motor goes, I will be taking a look at it soon. The guy who helped build it is a good buddy of my dads and has a 600hp 70 Camaro and a 450hp 67 Camaro. I trust his knowledge on the subject and in fact, he rebuilt the Quadrajet on my Cutlass a few years back.

I'm not really concerned with ETs so much. As I said, this will be more of a street car than anything and actually leaning more toward a road racer/autocross car than a 1/4 mile brawler. Sure, it would be nice to get into the 12s but I could really care less, I just want to have a fun car to drive that might surprise a couple of Stangs or Camaros...

Unless porting the stock heads would be better, I was leaning toward the aftermarket aluminum ones from Edelbrock. Like I said, if it takes a few years to put this all together, so be it. I want quality parts in this and I want it done right. I have always been a guy who likes obscure things and I am getting tired of seeing G body cutlasses stuffed with 350 Chevys. Nothing against Chevys or anyone who puts one in their car, I just want to keep it Olds and build a solid package that will raise some eyebrows on cruise night.

Thanks again and if anyone has any build specs on motors that they built and what kind of numbers they achieved, please post them!

 

[DoubleV]

Can't argue with a guy who wants to keep an Olds engine in his Olds!

Track ET's give you a much better picture on what level of performance you're looking for regardless if you ever actually race it at the track or not. Much harder to judge when you go off of HP numbers. Sounds like you're looking for a nice street car with enough balls to make it fun when you stomp on it. For most casual cruisers, low 13's would be considered 'fun' for a street car as long as it's torquey.

Edelbrock heads would not be a good choice for your needs IMO. They are made for big blocks and high reving small blocks, neither of which fit your bill.

Look at my weenie engine build in my sig. Look how mild it is. Best time was 13.83 @ 96.85 mph. That performance is a bit less than what you want but look how much more potential there is. A sleightly bigger cam, an extra point of compression and it wakes up. A cleanup on the heads with a good valve job and bigger valves really wakes it up too. Do that and you have a fun torquey street car which would get you mid/low 13's @ a little over 100 mph. Want to sacrifice a bit of steetability and mpg? Bump the CR up even more and run a bigger cam. With the right gearing and stall, you can get high 12's.

 

[jetsetw31]

X2 Double V. Even though your dads friend seems like a good builder, Most builders think they can build a Olds like a Chevy and that is the leading mistake.
The most important spec you have to have is the cam specs and manufacturer.
I just made that mistake. the build was basically good. I double checked all but the cam. I'm paying for that now. My cam is not street friendly. The power comes in at 2 grand and i wanted it to come in just above idle. I wish they did a stock rebuild. Now i have to do a cam change.
The stock 350 has a RPM range of Idle to about 6 grand. Even the famed W31 came just off idle to about 7 grand. Which was a miracle considering the wild cam that was in it.
Todays cams are an enhancement of the stock replacement cam. Some are better than others. I personally recommend Lunati and Crowler. Their grinds take the stock patterns to a high level.
T

 

[olds307 and 403]

The Procomps from Benard Mondello are good quality, just a rip off of the old Edelbrock's but $1000 a pair. Edelbrock did some improvements on their latest head. Just make sure you have flat top pistons before you buy them. The have bigger 188 cc intake runners, not huge but you need your compression up there. I would mill the heads, they have big 77cc chambers, to push the compression to around 10.5 to 1. Means bigger cam and more stall and you need the SBO Performer RPM intake to fit those heads, bigger ports. I heard builder say not to port match the intake, kills velocity. You also need the 455 intake gaskets, Edelbrock, SCE or Mr Gasket make them. You also need to mill the intake because of the head milling and thick intake gaskets.

 

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Thanks again for all the info and suggestions.

Regardless of how my dad's buddy built the engine, I still plan on pulling everything apart and rebuilding it. This motor was pulled out of the car and has been sitting for some time now. He wants $400 for it and it comes with a Turbo 400 trans.

Streetability isn't really an issue to me. This will be a weekend cruiser/occasional racer. If I have to run high octane gas, so be it. My dad has a 67 Chevelle with a 355 in it and some mild work to it. (Vortech heads, intake, bigger carb, and a fairly radical cam.) We calculated 400 hp at the crank and that car is a blast to drive. Now, it is a 4 speed car with 3.73s out back, but that engine really moves that car. I would like something along those lines for my 87. I'm not looking for some fire breathing, 700+ hp mountain motor that absolutely cannot be driven on the street. Rebuilding a 350 to W31 specs sounds intriguing to me...