Ok, its time... now I need your help.

[29Coupe348]

the season is just about over...its time to pull the motor and rebuild it....now i need your help...its a 58 block #3751872, 791 heads, tri-power...i want about 330-350 HP, how do i acheive this???...please give me a good combo...for budgeting reasons, im gonna keep my heads, but if i need to put in bigger valves, i'll do that....thanks,mike

[bowtieollie]

You are going to need 11:1 pistons and a cam with specs similiar to the 348/350hp version in 1961

[29Coupe348]

will 11:1's be ok to run on pump gas?....will it run hot with 11:1's?

[JimKwiatkowski]

I run medium grade in my 409/425 and it runs good.

[348NUT]

I don't think you'll ever achieve that horse power with your heads. The truck #333 heads have virtually identical ports as the original #1147 350hp heads and they're relitively cheap and available. I'd get a set and put in 2:06/ 1:73 valves and port them. I think it would be well worth the money! Aubrey sells a new piston design using the best of old designs.(the giveaway engine has them) He has also designed his own cam shafts that I've heard good things about. If you're going to use the tripower then I think some porting to the intake on the low side will help alot! I've also wondered if opening up the divider between the two barrels on the front and rear carb would help too along with carb spacers? And last but not least if you really want to be sure to get that horse power+, throw in a 409 crank. It will only cost the price of the crank core! No matter what combo you choose, use bbc rods! and of course, other guys here have lots more experience than me so if they disagree, listen to them :D NUT

[Fran Preve]

I STRONGLY disagree with the big block rods, they're quite a bit heavier and you don't need THAT unless your racing it regularly. A stock 348/409 rod WITH QUALITY ARP BOLTS is all you need. Remember small block Chevy's with stock rods and quality bolts are hammered every weekend at the drag strip. Just my 2 cents, I don't like over stressing a block not designed for the added weight of MK IV parts.

That said, I have a couple of sets of LS-6 "dimple" rods with 7/16ths bolts I'll sell for $300, and pay shipping. These are the stock rods used in LS-6 engines and they're new. They're going on Ebay this winter.

[fatride]

I have the recipe for a 330 hp 348 using 1960 lowpo heads with 2.07/1.72 valves. My old 348 was turning 14.6 at the strip and that worked out to around 330 hp. I did this with around 9.1 to 1 comp and hydro cam! Ran on 87 octane. :brow

[dq409]

45 year old rods are 45 years old !!!!!
Take your chances on fatigued metal ?

NOT ME !!!!!!!! ,,,,dq

[29Coupe348]

I have the recipe for a 330 hp 348 using 1960 lowpo heads with 2.07/1.72 valves. My old 348 was turning 14.6 at the strip and that worked out to around 330 hp. I did this with around 9.1 to 1 comp and hydro cam! Ran on 87 octane. :brow

fatride...i'll take that recipe. if your willing to give it...the motors in a 2500 pound 29 coupe, 330hp will be plenty for that.....thanks,mike

[2obnxs]

fatride,

I wouldn't mind having that recipe either. :) Mine's a 1959 348 250 horse right now and I sure would like to add some ponies under the hood when I do get it rebuilt.

[fatride]

Ok, I'll see if I have the specs for the 348 build somewhere. If I don't I'll write it out from memory. :? :doh

[29Coupe348]

sounds good....thank you.

[2obnxs]

Thanks, fatride.

[fatride]

We are still moving into the new house and finishing off the trim (towel rods. shower doors, bung wad holders :rolleyes: etc.) I have the specs written out on paper somewhere on the desk at the old house. I'll look tomorrow.

[2obnxs]

fatride,

take your time. just moved myself and i'm still working on all that same stuff.

[29Coupe348]

Fat, any luck finding the recipe?

[raymar58454]

For 348nut: Whats the info an the giveaway engine? I just found out about this site last night and am looking to replace the 350 in my 58. Thanks Ray

[fatride]

Naw, I didn't get to the house to look :mad: I could start with the easy stuff. Bottom end .010/.010 crank, Arp rod bolts, Clevite rod bearings. Crank micro polished oil holes chamfered. Rods and mains @ .0015. Pistons, Cast 9.5. My block was bored .060 due to top ridge damage. .030 over would probably lose 5 or 6 hp. Heads, 1960, 348, 379s with 2.07/1.72 stainless steel valves installed, Ports enlarged to Fel Pro performance gasket size, runners blended into port 1" with a pebble finnish. Pocket ported. Exhaust side enlarged to Fel Pro gasket size, ports polished. Valve boss turned down to accept teflon seals, 7/16" ARP screw in studs, Comp Cams Big block chevy roller tip rockers@ 1.72 ratio, Crane poly locks. Crane 99838 double valve springs and retainers with + .050 locks intalled height @ 1.720" Or 130 lbs on the seat and 320 lbs open. I have more but I have to look at my cam specs and ring specs. I can tell you this, detail, detail, detail. It's called blueprinting! Everything in these old blocks were made for mass production! They are rough. More to come. :D. Cam is High Energy 268 with 218 dgs duration @ .050 and .491 lift. Stock cast iron three two intake manifold gasket matched with the port opening sized to Fel Pro gasket size blended into the runner 1" with a pebble finish. Rochester three two carbs with .061 jets front to rear, accelerator pump shooters enlarged from .024 to .034, progressive linkage. block was deburred. This combo ran 14.6 @ 93 mph in the 1/4 mi. with 4.11 gears and a 350 tubo tranny. Engine ran on reg 87 octane fuel with 36 dgs total timing.

[348NUT]

The give away engine was raffled off at the convention a couple weeks ago. But, Glad to have you aboard! :clap We love our W engines around here and we highly suggest building one for your 58! :clap They are a little more spendy than a small block but well worth it! :brow NUT

[29Coupe348]

sounds good fat....thank you, mike