Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Hotrodding Basics (http://www.hotrodders.com/forum/hotrodding-basics/)
-   -   SBC Questions (http://www.hotrodders.com/forum/sbc-questions-227636.html)

fastnloud 12-27-2012 07:48 PM

SBC Questions
 
I have an 82 GMC Sierra with a built 350 and 350 turbo trans. Street driven.

Here are the specs on my motor:

350 4 Bolt Main .040 Over
Scat forged I beam rods
Keith Black flat top pistons 4v reliefs
Moly rings
World Sportsman II heads 2.02 valves and 64cc chambers
Edelbrock performer rpm intake
Edelbrock 650 carb
1 7/8 longtube headers
Lunati Bracket Master II Cam 300 duration
Crane Valve springs
Crane roller rockers
Comp Cams double roller timing set


Trans:
350 turbo
b&m rebuild kit
stage 2 shift kit
Hughes Performance 3000 stall

I haven't dynoed it, but the truck runs very well!

My questions are... what would I need to add/change out to make my motor a 383 stroker? How much more horsepower would I be looking at?

Also, would a tunnel ram intake make very much more horsepower or torque?

Thanks guys.

hcompton 12-27-2012 08:20 PM

A bigger intake should help with that cam. But will loose power down low.

A bigger carb seems to be in order 650 might not be big enough at max rpm.

A 383 kit will give you some more cubes but i would not tear the motor down to install one. If it was down for repair fine but a good running engine would not have much gain over 350. Now it should give you some more punch across the board. But to answer your question its only the crank andpistons that need replaced stock rods are fine. But i usally buy a externaly balanced kit with crank, rods, balancer, flexplate, pistons, pins. All balanced from the factpry to be drop in ready. Even if i decide to have the kit balanced by a machine shop for high rpm running. At least if its prebalanced it is cheaper at the shop. Also does not add much to the price of the kits. About 800 to 1599 is normal. Eagle or scat both make cheap kits.

What gear are you running the cam might not be happy with tall gears. Probably needs 411 min.

Some dyno tuning of the carb/timing will usally give up a few more ponies.

496CHEVY3100 12-27-2012 08:27 PM

Not much gain in horsepower ,but Big gain in torque , Horsepower sells motors TORQUE wins races

fastnloud 12-27-2012 08:32 PM

Thanks for the help.

I have 3:73 rear gears in my truck, it has some good low end pep, and turns about 2800-3000 rpm at cruising speeds of around 55-60 mph.

What type of bigger intake would you recommend?

fastnloud 12-27-2012 08:34 PM

Quote:

Originally Posted by 496CHEVY3100 (Post 1627734)
Not much gain in horsepower ,but Big gain in torque , Horsepower sells motors TORQUE wins races

Indeed, thanks.

fastnloud 12-27-2012 08:37 PM

Can you guys make an estimate on what compression my motor has with the specs I have listed?

496CHEVY3100 12-27-2012 09:05 PM

Without knowing compression thickness of head gasket ?41 mabe,tulip valves or flat,tapered top on pistpns or flat all the way to edge ,how thick are top ring lands,rod length,has block ben decked ,does it have 3.48 stroke or stroker notice bore .040 will raise slightly ,if all fairly close to standard approx 9.75

fastnloud 12-27-2012 09:07 PM

Quote:

Originally Posted by 496CHEVY3100 (Post 1627755)
Without knowing compression thickness of head gasket ?41 mabe,tulip valves or flat,tapered top on pistpns or flat all the way to edge ,how thick are top ring lands,rod length,has block ben decked ,does it have 3.48 stroke or stroker notice bore .040 will raise slightly ,if all fairly close to standard approx 9.75

Alright, thanks.

hcompton 12-27-2012 09:18 PM

I would suggest a edelbrock victor jr or rpm air gap(the tall one). Both will give you a boost in top end power but i think the rpm air gap is a little better for such a heavy truck. On the street you might already have the best intake.

Rpm air gap and victor will be hard starting in cold weather. Dual plane is better for street use in truck unless your going to for max effort.

But that being said the rpm air gap and a 750 carb will wake it up in the top end. But could cost et if its heavy and looses torque down low. But with 3000 stall it may work out. Would need a clear dyno results to figure where its lacking without driving it around. What you got is probably good to 5500 rpm but you may have a lot left over if it turns to 6500 7000 rpm.

I use this to figure compression Normal felpro gaskets are .041 stroke 3.48 rod length 5.7 bore 4.0 or 4.030 for 30 over. Deck hight is .025 if un cut with stock pistons not rebuilder pistons. They may be further in the hole.

http://www.kb-silvolite.com/calc.php?action=comp

fastnloud 12-27-2012 09:24 PM

Thanks, yeah it's a street truck only, and I do drive it in cold weather as well. Low end torque/power is most important to me.

vinniekq2 12-27-2012 10:08 PM

where did you get 1 7/8 headers? what kind of adapters are you using? I would use 1 3/4 headers for a hot truck engine. are the sportsman heads ported?

fastnloud 12-27-2012 10:15 PM

Quote:

Originally Posted by vinniekq2 (Post 1627782)
where did you get 1 7/8 headers? what kind of adapters are you using? I would use 1 3/4 headers for a hot truck engine. are the sportsman heads ported?

I bought the truck with them on there. They are suppose to be hooker super comp long tubes. I'm kinda looking around for some headers on the used market right now, that I want to paint black, so I'll keep in mind the 1 3/4 recommendation.

Also, I'm not sure on whether the heads are ported or not. I'm guessing the sportsman heads don't come from the factory ported, right?

vinniekq2 12-27-2012 10:33 PM

The sportsman heads can be nicely ported. Local here used those heads for quite a few years before upgrading to vic jrs. The car (67 Camaro) dipped into the 10s a few years ago with a 355.He then build a replacement 383 with victor heads.
The sportmans when ported flowed 265 CFM.
The headers you have should have a 7 bolt flange if they are 1 7/8 tubes. Those are big tubes...If they are hooker headers,make sure you buy the hooker pattern for the inside gasket if you replace gaskets

496CHEVY3100 12-27-2012 11:20 PM

Opinnions are like ? well everone has one ,Heres mine if i were going to do the majorty street driving ,I would used 1 5/8 for low & mediun rpm range 1000-5200 with a 355 leave big tube headers for high rpm and 406 -and 434 guys and light weight vehicles ,more tpurque where you will be operating, I run 1-3/4 on my big block 496 in picture above it is in a 1953 chevy p/u Very happy with results

vinniekq2 12-27-2012 11:36 PM

I can see using 1 3/4 inch header primaries on a 396,sounds like a good choice.
small block headers I see 1 1/2 inch primaries as a good choice for near stock applications. good point above


All times are GMT -6. The time now is 11:25 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.