cutlassefi

Here's the next build I eluded to in the 455 Intake comparison post.

350 block bored to 4.155
Offset ground 350 crank to 3.500 stroke
Scat SBC Sm Journal 6.00" rods
Icon 9943+.030 pistons
Lunati Custom Hyd Roller 216/221 on a 111, lift is .546/.529 with 1.6 rockers
7a Heads, filled, welded, 2.0/1.62 valves
Thornton Exhaust manifolds
RPM intake
750ish carb

This will be a driver, approx 9.25:1 compression. Yes it will be dynoed, maybe with headers and with the manifolds.

Should go to the dyno sometime in late Aug.

Thanks guys!!

captjim

Sounds like a fun driver. Just for informational purposes, what would the retail cost be on that assembled and broken in? If you are not comfortable saying, that is fine, jim

joesw31

This should be a nice build. Has the block been sonic tested?

380 Racer

Mark, I think you will do good with the 380 combo. Will be big bang for the buck. But I do think you will want headers on it IMHO.

coppercutlass

This is something I would love to build in the future. When money allows.

cutlassefi

No problem Jim.
Depending on the amount of headwork and the type of valvetrain it gets (flat tappet vs roller, roller rockers, stamped roller tip etc) it'll normally run anywhere from $5500.00-$7000.00 for a complete running and in some cases, dynoed motor.

But I start all block work with an align hone with new bolts/studs, square deck to my spec, boring with a BHJ Bor-Tru, (I don't know of any other Olds engine builder using this) and then honed with a BHJ Torque plate.

All rotating parts are balanced, and automatically includes a new balancer, flex plate etc. All clearances/specs are supplied with the engine.

Yes it was sonic checked, it still had around .200 wall thickness after boring.

cutlassefi

Owners' choice.

ah64pilot

Is the goal for this engine 325 HP? It seems like it should make much more than that...

kitfoxdave

Just wanted something with a bit more attitude... And a comfortable cruise...planning some long trips

380 Racer

A question........in my calculations a 4.155 is a .060 overbore? Not .030 over.

Oooops, I just looked, they start @ 4.125. So I'm sorry......MY BAD!

captjim

Yeah, the 4.125" is .068 over, then add the .030 and you are at .098 over. Most 350s can easily take that.

pilot, peak HP never tells the entire story, this should be VERY resonsive with tons of mid range yet good manners. Nice build, Mark.

coppercutlass

i was gonna build a .030 425 piston combo before my current .030 350 engine build. But i had cast pistons i decided i wanted forged for longevity .

ah64pilot

There's a guy on this site that built a .030" over W-31 engine that is fairly mild and it made 400 HP / 430 Tq...I just think 325 is shooting low for a 380. At least 1 HP per C.I. Should be easily attainable, especially with all that's in store. IDK, maybe my expectations are out of whack!?!

coppercutlass

Yes steve 325 seems low. But I bet the driver characteristics will be like stock . I would shoot for 450 with a set up like that. But to each their own.

380 Racer

OK, here is my two cents/opinions. It does need headers with a good exhaust system. I am no cam expert by any means but I think it needs more lift and duration on the exhaust side. Mainly because the heads will be basically stock (ie. no porting). This is all IMHO.

cutlassefi

I thoroughly enjoy posting stuff like this to get peoples' input.

Here's the deal. The heads will be mildly ported, mildly. Yes it would make more power with headers instead of manifolds. But he wants torque, not hp.
That's the reason I did the cam they way I did. The 111 lobe sep will have good street manners but the tighter duration seperation along with a slower lobe on the exhaust side will build more torque earlier. That's what he wants. This car will have a 200-4R with lockup.

And quite frankly, I don't believe a "mild .030 over W31" made 400/430. Not without head work etc.
I'm also not sure people know how much work you need to do in order to make 450hp out of a 380. Just ask Nick.

captjim

You really are exposing yourself of late with posts like this. 450 HP? Really? Do you have any idea how difficult that would be on a pump gas Olds 350?

You old-timers know my position on "Horsepower". At least as it is measured (really estimated, as it cannot be measured). HP is a function of torque and rpm. If an engine hits peak torque at a low rpm, low hp, but GREAT on the street. HP requires higher rpm power band, which requires gear and converter. BAD for the street.

I agree with Mark, NO WAY you are getting more that 1 hp/ci without significant head work. Remember the old Edelbrock Power package 355? 10 to 1, big cam, extensively modified heads, made 397 Hp at (I forget the rpm). And again, who cares if it makes 407 HP at 6500 rpm when it is going into a 4000 lb car with a 3.08 gear that gets driven daily? My wagon ran 13.9 shifting at 4600, was reliable, fun, and made 242 RWHP.

coppercutlass

I think it could be done with !!!!! Proper work. Even on pump gas. Like I said if I built a 380 strocker it would be . I guess I should have explained if I had that bottom end I would shoot for 450 hp with the proper work . I forget you guys can't read minds.

captjim

You can "think" all you want, not happenning. Not on a driver. Not N/A, power adder, sure. If I am wrong, show me one SBO stroker build anywhere making that kind of power. HP in a small block requires RPM, there is no way around it. RPM requires compression, cam, converter, and gears. No carbureted engines have a power band from 1500-6800 rpm. Again, you are showing your lack of real world experience. IMHO.

coppercutlass

I did say proper work heads compression and everything needed to get 450. I didn't say item for item on what mark is using to build 450. If ever said that then quote it. I said I would shoot for 450 with a set up like that . Meaning if I built a 380 stroker I would want to achive 450 hp. Dunno what your deal is but you should not read into what is not there. I should have worded my statement better.

coppercutlass

Imo its kind of pointless to do all this work to stroke a sbo. When you can build a 455 that would probably. Perform about the same with out all the expensive machining or exotic parts. Not saying its a bad idea but to each their own. My lasy 350 made 386 at the fly based on trap speed and wheight if I remembered correctly. It was driveable I drove it to work, cruise nights run errands etc.

ah64pilot

I guess I have a different opinion of what good street manners is. I'll just keep my mouth shut and wait for the results. It just seems like a lot of work and money are being put into the project...but it's not my coin.

coppercutlass

I love small blocks but if you are stroking an engine and doing all this "special" work chev. Rods, offset grinding the crank. Which is a lot of money for a goal of 325 hp. Why not just build a 455, or a 403 which at that power level should have no issues surviving . I'm not trying to be a debbie downer but I spent 2500 on a mild 350 that went 13.86 it has 10k plus miles and still runs with zero issues. Is there really no other options for a 325 hp build ?

kitfoxdave

Wow! Didn't realise my little cruiser engine would be such a controversy... Just want to squeal the tires every once in a while. She's not going to the track, but on the open road... With good manners.
Thought about the 455 long and hard, but decided to go this way instead. The manifolds will help with the stock look and flow a bit better. Headers might be an option down the road.
Yes it could make more hp, good, fun is my goal... (of course there are many opinions on good fun!)
As far as the cost, well nothing compared to the Jacobs r755 radial engines that i need overhauled.

coppercutlass

My little 350 could roast them and had great street manners. But it's your project you can do as you wish.

captjim

The only extra cost is in the extra boring and offest grinding, maybe $400?? There are no off-the-shelf SBO rods, so SBC must be used. I completely understand why guys go 455 when they are similar in size and weight (a little taller and wider), but I am fond of the little 350, too. IMO 403 are a terrible platform for a performance build and have a long track record of failures.
I promise you that your $2500 engine does not have the quality parts and machine work that this one will.

captjim

It is my position that by the time you get the head flow, compression, and cam required to make an honest 450 HP, the car is long longer a pump gas driver. If it is so easy, do it, nobody else has.

captjim

What are the specs on this combo?

bccan

This build is similar (sans stroking) to 350 previously in my car & it was an excellent street engine although you had to run good gas to get away w/ 10+ CR & iron heads. I had the cam that is In my present engine, big valve, filled, unported heads w/ Super Comps & 2.5 x pipe. With a 200-4R, 2400, & 3.90 it ran all over the 13's depending on my lack of driving consistency & ability to find traction. IIRC it made 290hp @ the wheels on a brutally hot & humid day so one could arguably round it off to 300.

I think the cam was pushing limits of what I consider good manners, especially from an idle standpoint. I had actually stepped up to that cam from a smaller one because of preignition issues, had to bleed off some pressure. With the gearing it never was a dog down low, it took off very well from any speed or rpm but definitely put on it' s Hulk costume around 3k.

I think this is a well planned build & should run really nice but I would run w/ headers & a nice quiet exhaust system right out of the gate. I do understand the logic of nice quiet manifolds & I did start off that way only to spend more time & money soon after on header/x pipe system. My kid's car w/ manifolds & same exhaust system actually seemed louder than headers do. Sort of less ambient @ the front of the car but louder out the tailpipes.

The advantage of the small cube engine for the use it seems this car will see is that it will be able to put down some satisfying performance & I'll almost bet it will return 20 mpg on the highway w/ a decent tune. Maybe Mark can step him up to an EFI & it will pull 22+ !

coppercutlass

Specs on the 13.86 combo where. 1973 350 w/ 14 cc pistons. 1972 7a heads. Edelbrock intake performer. Eddy 600 cfm carb, proform hei, long tube headers, with a 260 h comp cam, a 2200 stall, with a th400 trans, and 3.73 gears out back.

cutlassefi

I never said it wouldn't make more than 325hp. I just said that was the goal, with the emphasis on TORQUE.

Some of you can't read.

kitfoxdave

Should beat the heck out of the tired old 350 with #8 heads that was in there!

cutlassefi

Actually only about $250.00, about a $100.00 extra for the crank and $150.00 or so on the block. I already have to pay for the BHJ Bor Tru setup so it's just a few cuts more after that.

captjim

This is the supposed 386 crank HP? Really?? That ET is nowhere close to that. Neither are the specs. 300 RWHP will put a street trim G-body in the high 12s. Again, my 300 flywheel HP 355 ran 13.9 in a heavier car.

To Mark's point, I have said a gazillion times that HP is over rated. On a street car it is all about throttle response and torque. A milder build might give up a few HP up top, but will be more fun to drive, and isn't that the point? And, the strong bottom end is a good foundation if more punch is added later (hint....N2O!!!)

coppercutlass

No thee 386 one iis the one that gave up. That was the 13.86 e.t. The 386 was 13.3 with a tight converter and carb that was too small. That was . 350 with flat tops cast. A 280h comp cam. 6 heads shaved, with big valve springs etc. Roller tip rockers. Edelbrock rpm intake. Compression was around 10 to 1. Same hei amd headers from the previous set up. Same with trans. It probably would have hit 12's with the propeer converter and carb. It's fastest pass was 13.30 @ 103 mph in the heat. But it sounds right..

captjim

Not sure how you got to 386 HP, the numbers don't add up. 103 MPH works out to around 325 flywheel HP.
http://www.dragtimes.com/horsepower-...power+Estimate

coppercutlass

the claculator i used wheight and e.t. got me 382. 13.30 with the car wheighing 3600 lbs but thats all it used dunno how correct it is but i see what you are saying. it also had another calculator which said the same thing as yours pretty much. but then the one with the wheight and e.t. said 382 hp at the fly and 294 at the wheels. Keep in mind i did have a tight converter and smaller carb. so while my mph could have been for a 13.0 12.9 e.t. pass which i have been told that sounds about right i wasnt putting the power down right and once i had it right parts failed. if i would have made a 12.9 pass with same mph it would have been 319 hp at the fly with the link you provided btw thanks for sharing that . I could sit here and talk about all the shoulda woulda couldas but based on what it ran thats what it did i guess . but it sounds right on one You said 300 rwhp would put a g body in the high 12's my car could have been capable of that if i had the right components. the one calculator i used said 294 rwhp . It's starting to get confusing. My car could have been capable of high 12's but it died so it didnt .

captjim

If the car only weighed 3500, that makes HP even lower

Here is the point. Mark posts a build using quality parts, machine work, and assembly. His cost and expectations are reasonable and reflect REAL WORLD EXPERIENCE. I get aggravated when guys like you pop off with
"I have a $2500 13 second build" or
"My mild 350 made 386 HP" or
"450 HP on a pump gas SBO SHOULD be easy"
Then guys who don't know any better think it is easy to put together a decent engine with an unrealistic budget. I left OP over a similar dispute. I posted my 355 spec sheet, around $4000,
https://classicoldsmobile.com/forums...arts-list.html
A bunch of guys ripped me, including the owner of the site. I got tired of it and left. He now realizes that I was correct, cheap-azz builds don't always work out.
I just don't understand the mentality of guys constantly promoting doing things as cheaply as possible on this and other Olds sites. Do it right, do it once. Sorry for mucking up your thread Mark, I will cease and desist.

coppercutlass

That's what the game plan is on the next build. I got a new job make a little more money and i got a running 307 to enjoy the car while i build a great running 350 that can runs 12's all day n/a to the track and back. If you include the cost of my heads and what im investing in my bottom end your numbers are dead on. That wheight was also with out me in it forgot to include my wheight . but probably closer to 3600

cutlassefi

No problem Jim. We're on the same team.
I get frustrated too. But I always remember the famous saying;
"If you didn't have enough money to do it right the first time, where are you going to find the money to do it right the second time."
I'll post the build as it progresses.