Just build the 350 for now if it was me....if it is budget you are shooting for a 350 is hard to beat and will run hard if cammed right.....
I know....was and still am poor white trash...lol. I have built engines that cost more than my whole car....over and over.....and my own engines were 355's for years....a 450 horse 350 is a bag o fun with a stick shift.....that is 360 to the tire and 50 more than a Ram Air LS Trans Am throws down....and those run high 12's at 3600 lbs.
There are some fast 350's out there....believe me.

Jebby

 

https://www.summitracing.com/search/...-crate-engines
What do you think of this?

 

A 350 inch engine with AFR 180's will scream with the right cam, compression and gearing. I'd optimize the current combo, but that's me. The 383 isn't a bad option with those heads and reusing your current block, etc. and will give you another 40+ lb/ft torque over the 350. Or, build the 406 and start with your current heads. You can always upgrade the heads later if you don't like the powerband. It's a hobby so do whatever makes you happy.

 

Hey Jebby...

Got the specs and parts for that build listed somewhere on here?
I have one 383 in the works but debating either a bigger SBC or a LS.
Txs
Dennis (Bman)

 

My 350 is built and in the car, as you can see in the picture on the first post of this thread. The specs are there as well. And I plan to get a chassis dyno this summer to see what it does. Maybe I will be surprised with the numbers. The one thing I have learned is maybe I should cam it with a little more lift, and maybe single pattern. As for duration, the bigger I go is just going to move the torque higher in RPM, opposite of what I want.

Thanks for all your help. I am doing nothing till winter, so I am just going to keep researching and thinking about what I should do. I have been driving the car, and the engine does have some juice, its smooth and has awesome throttle response. Maybe I need to appreciate what I have.

 

Of course all of this is why they make big blocks and big small blocks!!

Two different animals.

You can make "torquey" small blocks. I really liked the LT-1 in my '94 C4. It was done by 5300-5500 or so...but was a lot of fun to drive with the 6 speed. It ran 13.20's with 100K+ miles on it in 100* Houston track conditions. Would be an easy 12 sec car on stickier tires or cooler weather and it was absolutely dead stock. Got 28 MPG too!

I'm doubting that 525 lb ft at 3500 RPM. I suppose it's possible if you did everything in the world to kill top end power...but you don't see it very often. Most folks want them do pretty well on both ends.

JIM

 

Read my build thread "Picked up a 72'"
I listed it in there.

Jebby

 

To the OP, from what I read it sounds like you are going totally off of feel. You mentioned you do not race and have not been on a dyno so you dont really know what kind of power you are making. However you're solely going off the butt dyno, this can be tricky. I have had tq monster engines that are so much fun on the street but not real fast cars at the track. Are you figuring that the 500tq number is going to be the sweet spot for you? That's a ton of tq for a fun street car and will rip tires apart which is what it sounds like you want. However for me at least, I start to get numb to power and I haven't currently hit the "I have enough power" spot in any of my cars.

In my '69 vette I have a peewee 350 thats .30 over its got full ported and polished Trick flow heads on it, 11.6:1 pistons and a solid flat tappet cam. It runs good but its no power house by any means. But I got a 4 speed and 4.11 gears and it is fun! My shift light is set at 7k so by the time I see the light and pull the gear she may be 7,200-7,300 rpm. I have not had a solid pass in the car as I have been battling traction and breakage issues but on crappy passes it consistently runs 12.1@120 so if I can get a good leave it should be a solid mid to low 11 car. I figure the engine makes 450-475hp maybe low 400tq

I have been planning a new build which will be a big inch small block something that makes 600'ish hp. But this is strictly to hit the e.t goals I want.

I think its tough for you since your going completely off feel in the car. Have you been in a car that makes 500+ foot pounds? They are fun but like mentioned your current combo with some gear may get you the wanted feel.

 

We live in interesting times: a 350 with 180 heads is a screamer, a 406 with 195 heads is a truck motor and a peewee 350 traps at 120.

 

LOL! interesting indeed! My little peewee is only pushing 3,100 pounds down the 1320. It's light so its not unfathomable, I don't need a lot of power. This was also before all the aluminum parts I did so she may be a little lighter now.

One day when I have some real power it may actually be fast!

 

Pushing a streetable 3100 pounds to 120 makes you at least PEEWEE in my book. Nice work

 

IMO the best way to get big power in a small block package is to go LS! Depending on how much money you wanna throw at it you can get an LSX 474 but if you wanna stay more on the pocket friendly side just go get an LS3 from a junkyard. Its not real hard to get 500-550hp from an LS3 plus the tq yield is about the same as the hp. I am pretty sure the LS3 in my 2012 Grand Sport is making about the same power if not a little more than my lil 350.

I really considered going to an LS engine in the '69 but I wanted to keep it old school.

 

I wasn't going to mention it since the OP was focused on original style engines but I've switched to LS power for most of my current projects. Here's an LS3 with a cam swap for my '69.

 

If I was going to make a major change like an LS engine, I would just go 454 big block.

All the information in this thread has been appreciated, but frankly, the only thing I can gather from all of it is that the right way to build a 406 is to abandon my AFR 180 heads and my 1-5/8 inch headers. It makes a 383 maybe a better direction, although it will certainly be less of what I want than spending the money on a Dart SHP block, some good 200 plus heads and another header set.

I am just going to sit back and think for awhile before I do anything.

Maybe if someone would just buy my engine as a whole package, for enough money, I could think about starting over from scratch. When I built this engine, I took a lot of advice from this forum, and I think that as a 350, its pretty well built. Maybe should have picked a cam with more lift, but otherwise, I thought I was doing the right thing and spending the right money.

It just simply does not push me back in the seat like I think it should.

 

Last comment fro me on the "push back into the seat".
If you look at the dyno charts for any othe motors discussed here, you see torque peaks before HP....pretty standard.
Kicking you back into the seat is the torque kicking in early and hard.
Now....add the other factors....car weight, how well you hook up, and trans X rear gear ratios.
My 67 Camaro without a/c was lighter than 3100 lbs (lighter than any stock SBC C3).
It also had 4.11 posi, BW Super T10 (just on the market as an aftermarket item) with a 2.64 1st gear. I had Lakewood traction bars and what we called a torque strap on the motor (we use to break the poli motor mounts on the drivers side). Nowadays we use solid motor mounts instead. H70-15 rear tires and c60-15 front tires.
Dump the Revlok clutch at 4500rpm and the front left wheel came off the ground. And kicked my azz into the seat.

Point being.....engine torque, cubic inches and hp are not the only factors involved obtaining that much desired "kick you into the seat" feeling.

Carry on.

I'll be interested to see your final outcome.

Bman

 

I thought of one thing that maybe explains even more my position. I have owned many Harley Davidson motorcycles, including 73 Shovelhead. I built that Shovel from a 70 cubic inch motor into a 93 cubic inch motor. That thing would pull out of every gear, and chug ahead and I almost could feel every power stroke pushing the bike forward. On the other side of the spectrum, you have Japanese rocket bikes that run 12000 RPM and up to get their power, and they clearly are WAY faster than any Harley. Harley motors can't even approach 12000 RPM, but they easily can go 100 mph on TWO cylinders. Harleys are all about torque. I have zero interest in 12000 screamin RPM no matter how big the HP numbers are.....just not interested.

So you can see the parallel. I am looking for that Harley style in the Vette engine.

 

As Jebby and others have stated a 355 built correctly will scream...You guys know lots more than I do about building gen 1 SBC's but my 355 L-82 block motor is fairly close to the OP's and I specifically built it for mid range torque plus it pulls hard to 6,000 RPM. I did lots of research on my own, spoke with many of you on the forum, and consulted extensively with the local Chevrolet expert in my area who has built 1,000's of motors including lots of LSX's and BIG HP motors from all generations. Here is where I ended up:

L-82 OEM block .030-355
Howards Roller cam (219/225, LSA 110, Lift .525/.525)
AFR 180 heads with .015 head gasket
Compression 10.2:1
OEM Super T-10 4 speed with 3.70 gears
1 7/8 inch LTH's

The interesting thing is not a lot different than the OP's but has the margin in many areas that probably add up:

Little more compression-0.2
little more duration and significantly more lift-+1 intake/+1 exhaust duration. .525 lift versus .500 and less
3.70 gears versus 3.55
1 7/8 inch headers versus 1 5/8's

All those difference must matter because I have zero desire for more TQ at the moment but the LS7 being a monster in the C6 does not hurt either.

Car is a total blast with very strong torque 2,000-4,500 RPM and rips to 6K with no HP drop off. Simply amazing!!! As fast as my 10 C6Z06? No but damn fast for a C3..easily outperforms stock C3 SBC and BB's..easily. Probably has more TQ/HP than most crate 383's by a wide margin.

 

JB, what I see you have that makes your motor better than mine is that additional lift and the 3.70 gears. The duration and LSA is essentially the same. If I was starting over, I would definitely use the same Howards cam as you have. Gearing....?? I like the idea of driving enough that I am not sure I want that much RPM at cruise speeds. My 3.55 is something to get used to after driving modern overdrive cars.

 

I agree..cams are close. Yes I think the howards cam with .525 lift is key. If I could get the duration with even more lift like .535 I think there would be more power. Yes the 3.70 gears make the car a rocket but are annoying on the highway...my 10C6Z06 turns 1,800 RPM @ 80 mph in 6th, gets 28 MPG, 0-60 in 3.6 sec and the qtr in the mid 11's(some bone stock C6Z06's do 11.2 in the quarter)..amazing car.

I would not underestimate the big tube headers with AFR's..I went from 1 5/8 inch shorty's to 1 7/8 inch LTH with no other change and the character change of the motor from 3,500-6,000 RPM was very noticeable.

I also use a ported OEM L-82 aluminum dual plane intake.

I think that your best course of action is to maximize the sturdy platform you have now...bigger headers, intake? (don't know what you have now), cam change, etc.

NOTE: I recently optimized the Holley 4175 650 CFM carb....Had to go up 5!!!! jet sizes with the 1 7/8 inch headers and for the new motor..I knew that the 63 primaries were too small from the start...after the rebuild. 3/4 or more throttle in any gear noticeably lifts the nose and I have a 360lbs rear spring.

If your are going to scrap the motor, 406 all day, every day..I would forget the 383 over the 350 or 355. Not worth all the effort to maximize the cubes for 25-30 ftlbs of TQ at 500 RPM less. Just me.

 

As you have found out, the advice on the Corvette Forum is all over the place with an emphasis on RPM and HP. If you want to find out about torque and high performance torque you should check out a couple of 4 wheel drive truck pulling forums. These guys want monster torque and want it all by 5000rpm. Do some research and I'm sure you can find the answers you are looking for. Truck and tractor pulls, in Western PA start in late summer and run through fall. It's worth the price of a ticket to see these machines at work.
Jerry