1968 350 olds

[cutloosecutlass81]

I know I asked this before but I have more information this time so I'm wondering what kinda hp I'll have
Specs:
350 olds .030 over
Speed rpo forged pistons with 2 valve reliefs
#5 heads 3 angle valve job shaved and big block valves
307 bronzed lined connecting rods (for nitrous)
Stock polished crank
Edelbrock performer rpm intake
I believe patronix street or strip distributor
High volume aluminum milo den water pump
High volume oil pump
Comp valve springs
Comp roller tip rockers 1.6 or 1.7 ratio bigger studs
Comp cam .520/.523 lift 274/286 duration
Block decked
Flowtech headers 1 5/8 primary tubes and 3" collectors
750 cfm carb
March serpentine system
3" dual exhaust with x pipe and cutouts no cats
Summit pro torque mini starter
And a 75hp shot of nitrous (probably only use once or twice a year)
I'm pretty sure that's it I'll update if I remember anything
11:1 compression

 

[L92 OLDS]

The 68' block with #5 heads are some good parts to start with. Guessing your hp is a crap shoot and depends largely on your tune but I think 350 hp without NOS is possible. Have you searched through the engine build combo / dyno sheet forum at Realoldspower.com?

 

[86-blk442]

I would definitely agree, 350 hp would be a nice conservative number to aim for. Its all going to be high rpm power though with a cam like that. Whats your intended use for the engine? I had a 280H in my 350 and hated it on the street. It had no low end and ate fuel.

 

[olds307 and 403]

Don't go 11 to 1, unless you want to use only race gas. You should be around 10.25 to 1, which is plenty. Don't dwell on peak hp numbers, although with BBO valves and bowl work 350 hp will be easy. Olds, including their 350 are know for a nice flat torque curve. Totally different then a sbc, I like them much better.

 

[cutloosecutlass81]

The main use for the car is just street or strip nothing major and my engine guy said he's gonna have me at 11:1 and to run only 93 or up which I'm not complaining the most it'll be driven at one time is to break it in and after that it'll just be a weekend warrior or car show car not gonna be driven a whole lot in a year and thanks guys

 

[DoubleV]

What are the full stats to that cam? Doesn't appear to be a good fit for an 11:1 engine ( which is way more compression than you need and have doubts it would run well on 93 ). Also, were are you finding 1 5/8 headers for an Olds in a G-body? I would think 1 3/4 headers would be better anyway. All my opinion.

What are you looking for this thing to run and with what setup?

 

[cutloosecutlass81]

I'm pretty sure I can't go any lower than 10.25:1 on the cam and the spec card from comp cams doesn't tell me

 

[86-blk442]

So are you planning to race the car at all? If not and you're just going to show and drive it, why go with such a high compression ratio and lumpy cam? I have an XE262 in my 355 Olds with #5 heads w/w31 valves, shaved .038" and bowl blending, performer rpm, q jet, 1 3/4" long tube headers, and about 9.5-10:1 compression. It's got plenty of get up and go, doesn't suck gas even with the 3.73 gears and keeping it out of overdrive, and won't require anything more than 91 fuel..

I dont think that cam would need such high compression. I was running my 280H at my current 9.5-10:1 and it performed well besides sucking gas and having poor street manners.

 

[DoubleV]

I'm pretty sure I can't go any lower than 10.25:1 on the cam and the spec card from comp cams doesn't tell me

It sounds like you're trying to build the engine around the cam. You're supposed to pick a cam that will work with the rest of the build so you usually pick a cam last. Also, you should ask a cam/engine builder expert ( one skilled with Olds ) on a cam recomendation because they know what works and what doesn't. Average 'Joe machineshop guy' only knows Chevys and the average forum posters aren't cam experts ( plus you'll get bombarded with too many choices ).

I'll repeat my question from my previous post; what are you looking for this thing to run and with what setup? The answer to this is critical in knowing how you need to build the engine.

 

[86-blk442]

I had Bill Trovado build my heads and I also got to talk a little tech with him when I was at his shop. He really seemed to know what he was doing and I would definitely recommend his book on Olds engines.