Pulling the 350 next week and want to get roughly 350 hp out of the rebuild. What would you guys recommend to achieve this?

 

Is the motor completely stock? What heads do you have? Are you going full out rebuild with new pistons and are you operating with a liberal budget?

Just off the top of head- 350 Hp is more than likely going to mean 9.5-9.8:1 compression, head work, high performance intake, larger duration cam, upgraded ignition.

 

Proper machine work with flat top pistons, either Speed Pro, Probe or CP. Then head work with the bowls opened up and 2.07/1.625" valves and springs to match the cam Cutlassefi picks for you. Depending on your rpm goals, aftermarket rods, 7 quart pan and use a good Cloyes double roller timing set and degree the cam.

 

Motor is stock with new performer intake, plus carb has been rebuilt with updated ignition and headers with 2 1/2 exhaust. The gears in the rear have been upgraded to 342's also. Planed on having everything machined. Wanting to spend under $3000.

 

350 for under 3k may be difficult.
Just gonna throw some recent numbers.
Pistons- 400
Rings- 100
Cam/Lifters- 250
Performer RPM- 400 (to my knowledge 350hp with anything less is tough)
Machine Work? Shop Shop Shop but I paid well over 1,000 for crank cut, cyl bore/hone, deck square and assembly.
I didn't have any machine work done to the heads, just springs/guides/valves/bridges etc.

 

the machine shop quoted me $1350 for crank cut, cam lifters and all seals and gaskets rebuilt back to stock specks ready to bolt back in. Everything over that stock price was extra.

 

Sounds like a reasonable price point.
Few things
-What cam/lifters?
- What are you plans with the heads (7a?)
-When you say "everything over that stock price was extra" does that mean if you swap in a larger cam they going to charge you extra labor or just the price of the part?
-Are you upgrading the carb?

 

Your Qjet, assuming, will probably need idle circuit mods for the bigger cam that 350 HP requires. Don't forget you will probably need a 2500 stall converter minimum to make it work.
Bigger valves and a good bowl blend would be a minimum for 350 hp along with much stiffer than stock springs, whatever is matched to the cam.

 

7a heads yes
just extra on the parts price not labor
have a holley ready to put on
what is a good cam/lifter setup for these olds?

 

What kind of Holley?

-I have a comp xe 268.
Reasons:
- I chose it because the lift was below .500 and I was keeping my stock sized valves. Several articles and books and experts here have made it clear that stock style heads don't flow all that well about .500.
- I wanted something with a noticeable idle, big power band (performer RPM and 2400 stall).


-Before you select your cam I'd get a little more in the build because you can get a custom ground cam at a very reasonable price (PM Mark R. user-"Cutlassefi" for details)

All that being said- I love my xe 268
http://www.compcams.com/Company/CC/c...csid=1171&sb=2

 

picked up the engine today and installing it this saturday, this is what the builder did to the engine for $1790

 

Look forward to seeing the finished product.

 

That's pretty cheap I have 1200 alone in machining to my short block 355 . Well over 1000 in parts. And the heads are well over 2k but they are ported and everything is new. 2 diffrent extremes but same machining applies to stockish builds.

 

The builder has been using the same parts supplier since 1973 in Louisville and he said if he used anybody else the parts would be well over double the price. I thought it was very cheap to have done. We have used him for 25 years he is a very good guy and does great work.

 

As you can see I'm an Erson dealer but you asked our opinion so here goes;
Cam is too small for piston/compression, OR the piston/compression is wrong for that cam.
And if you don't have a Performer rpm or similar on it along with headers you won't be making 350hp. Sorry.
Is there another list of machine work performed? I didn't see balancing on there anywhere.

 

I have the Edelbrock version of that cam with 9.5 to 1, it pings on 91 Octane Shell gas unless everything is bang on. You will be higher than that for compression.

 

Yeah, I noticed that .448" lift / 204º duration cam. I am not engine builder but I don't see any way that cam can achieve 350 horsepower. I had a same lift/duration cam in my engine back in the 80s and while it drove great and was peppy, I remember getting my *** handed to me by bone stock 403 Trans AMs.

 

How far are those pistons in the hole and what did the heads CC at? My speed pros fell .025 in and my heads were off of factory by +2 cc. With similar results you'll be 10:1 at a minimum.

 

10.25 compression and 64cc heads

 

Who built this motor? I could ship my motor to him have him do the work and ship it back and come out ahead of the game.

 

Your gonna need this

 

That's a wicked price, Is it what you were expecting? If so I think this engine builder may be very busy soon.
let us know how it runs.

 

If this motor isn't in the car, change that cam! Mine was pinging from too tight a choke setting, obviously too rich a mixture can also cause pinging. Not used to a properly calibrated Qjet, needed the choke cranked tight before. I am running a fairly aggressive timing curve but backed down my vacuum advance to 14 degrees and switched to ported vacuum. I only eliminated it this time by putting NGK 5670-8 vs the hotter XR5 heat level plugs that was in there. Honestly, that cam is mediocre at best, although that one has a 112 LSA vs 114 LSA on the Edelbrock, it is just too small. When I put on these heads, I should have bought the Comp 280 H the guy was selling. Two guys at our track were running it and much faster than me. But I didn't want questionable power brakes and a rough idle. Cutlassefi can give you the best of both worlds, decent manners and a lot more power than that cam.

 

Not a good day for the 442, we got the car loaded up and in the garage with the motor installed and everything prepped and fired her up and she ran perfect for a few minutes and then she died. Took the valve cover off and number six either had a defective spring or valve. Now the motor has to come back out and back to the builder. Sick to my stomach right now.
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That sucks, seriously consider a different cam, now it is coming out. Hopefully he makes it right at his cost.

 

Funny thing is a 1970 350 4 barrel engine is 310 hp factory, only 40 more horses could have been found in a set of headers, RPM intake and a good Holley 750cfm carburetor.
Until the owner's mind set eliminates the word "mild" and decides they really want to build a strong engine, 204 cams, Performer intakes and quadrajunk carbs have to be eliminated from the "use list".

 

Disagree on the Qjet, the can be tuned for nearly any combo. My APT is a 5 second adjustment at the track and secondary rods are similar.

 

sorry to hear bout the break in going wrong. Hopefully it gets corrected and i second finding a new cam. I loved the comp 280 h cam. even with a tight converter it layed down good 1/4 mile times and performed well with a 600 cfm carb.

 

I have a 1972 with only 180hp and the motor broke a piston so I had to rebuild the motor or I would have kept it stock......

 

Yeah, on paper using GM's fantasy "GROSS" rating methods.

Same engine with 8.5:1 compression in 1971 was rated 260 hp GROSS and 200 hp NET. I highly doubt 1.5 points higher compression on the '70 engine translates to 50 more horsepower in the real world.

And then there's my personal experience of back in ~1982 running my stock '70 Supreme 350-4bbl 2.56 rear against a friend's '71 Supreme 350-4bbl 2.56 rear. I thought I'd "whup him bad" with my higher output engine but the cars were nearly even up until the top of 1st gear when I pulled a head just a bit. It sure didn't feel like I had 50 more hp than his car.

 

1: Horsepower ratings were taken at different RPM in 70 and 71.
2: The driver is 99% of the results of a heads up drag race.
3: 1.5 increase in compression is everything.

 

Yes, but it's only 200 RPM. Would that make much difference in the output?

1971 350-4bbl specs:
GROSS Ratings: 260 hp @ 4600 RPM, 360 ft-lbs @ 3200 RPM
SAE Net Ratings: 200 hp @ 4600 RPM, 300 ft-lbs @ 3200 RPM

1970 350-4bbl specs:
GROSS Ratings: 310 hp @ 4800 RPM, 390 ft-lbs @ 3200 RPM


I highly doubt 1.5 points higher compression and an additional 200 RPM = 50 horsepower. What I see as the real difference is the rating method.

1970 and earlier used a bare engine on a stand, with no accessories or mufflers (during this discussion years ago someone on ROP said the engines were blueprinted and running on special fuel).

1971 and later were engines as-installed in a vehicle, with all accessories connected and a full exhaust system.

Now THAT could result in a 50 horsepower difference between '70 and '71.

 

HP was measured across the same range of RPMs in all years. The PEAK (which is the published number) occurred at a different RPM from 1970 to 71. This was due to different cam, lower compression, etc. 1971 was also the first year for SAE Net HP measurement, as opposed to the gross measurements that ALL automakers used up to that point (not just GM). 1971 was the only year that Olds published both the gross and net numbers, so you can easily see how much of the reduction is in the test method and how much is from emissions detuning.

 

Didn't all 350's run the same pathetic .400" lift cam, except manual trans cars and the W31? I gained .5 in the 1/8 with a 1.5 compression increase. But there is ported, big valve heads, better exhaust, custom Qjet and 1.72 roller rockers. As 71 said, just the compression increase is minimal. A big part of the W31 package is the big duration cam and 3.91 gears.

 

There were three cams used in 350 motors in 1970:

P/N 400084, 250/264 deg, .400/.400 lift, 36 deg overlap, used in all 2bbl and 4bbl AT motors
P/N 393859, 286/286 deg, .472/.472 lift, 58 deg overlap, used in 4bbl MT motors
P/N 402194, 308/308 deg, .474/.474 lift, 82 deg overlap, used in W-31s

For 1971 there were also three cams used in 350s:

P/N 400084, 250/264 deg, .400/.400 lift, 36 deg overlap, used in all 2bbl and 4bbl AT motors
P/N 402486, 262/274 deg, .440/.440 lift, 48 deg overlap, used in 4bbl MT motors
P/N 409717, 250/264 deg, .400/.400 lift, 32 deg overlap, used in D88s

 

Any word of what went wrong with the motor? Are you jsut takign it back to them or going to open it up yourself and look too?

 

WOW no sir

Quadrajet versus Holley 750 LOL no gain there
What is a RPM gonna do crap stock heads and small valves and tiny cam..... nothing
Also the dude used W31 pistons in his build that takes it nearly or already out of pump gas 93 range. Hope he didnt fire it up on 87 octane

Big valves and bowl work, and a good bit more cam at the least

 

If you bolt on a 750 Holley in place of a quadrajunk and your car doesn't run better then your whole engine is junk in the first place.
I haven't seen 1 quadrajunk on a car at the track in 20 years!

 

You must not get out much or are surrounded by imbeciles

 

1- Crap stock heads? correct me if I am wrong but a 7a head flows more on the exhaust side than a #6 AND #5 head with the same advertised 64 cc chamber? Intake difference on is also larger than a #6 head in stock form.
2- Of course an RPM is going to make a difference with the right set up. 3
3- I'd bet I'm making 300hp+ with my stock sized #6 heads so I'm thinking it's possible with the larger 7a in stock form.

Heads info:
http://www.442.com/oldsfaq/ofhed.htm

As far as carbs:
http://www.hotrod.com/how-to/engine/...retors-tested/

Note the phrase "won out of box HP contest"