[houston4x4]

hey guys i am looking for some simple information here.. i just got a 1988 chevy k5 blazer 4x4 with a 350 in it. i was thinking about going to a bigger engine with more grunt possible a 383 is what im thinking? but i dont know if that would be a right choice for me. does anyone here have any tips or experience in it? the truck will not be a daily driver but i will be going into mud and all that kind of stuff.

the truck specs are as followed.

1988 k5 1500

350 with Auto tranny 4x4 detroit lockers in the rear with warn twist lock in the front

8 inches of suspension lift with 3 inches of body lift

38.5 super swamper TSL tires
thanks guys

[DoubleVision]

A 383 would do nicely, your 4x4 will benefit from more torque, and the 383 is the ticket for that.

[400smb_s10]

im all for the mudding and so are my friends and these are some of there motors they range from 300hp to 750hp list of them are 327 bored out with 389hp 422ft lbs 350 bored out to a 355 378ft lbs with 330hp 454 bored and stroke out to 589 hp 525ft lbs 400 sbc bored out with 385hp 365ft lbs a 383 512hp 550 ft lbs and a 427 bored out with 749 hp with 665 ft lbs im working on a 400 small block right now just looking into cams and heads and stuff right now i need to lay low on the pocket book right now with that said i think that the 383 with the right combination heads cam gears etc would be good for your outfit i have fullsize chevy frame shortened with a dodge dakota body on it 39 inch super swapper boggers and i recently had a 350 in it and it hauled *** hardcore so the 383 should be better for you application with the heavier body anyways i hope you get a little better idea from this sorry if it wasnt any help but the 383 is a good motor and if its built right it can have some serious torque

[houston4x4]

well ive heard alot about the 383 stroker.. never built one myself.. from what i was told its just a 350 block with a 400 crank in it and some good heads... now the heads that are on the k5 already have 1.94 , 2.02 valves in it. but what im wanting to figure out mainly is would i be better off just trying to run this motor and beef it up . or should i try and go have someone build a 383 stroker? what im looking for is proformance, and the lifetime of the engine.

[400smb_s10]

well i can guarentee that the 350 engine isnt going to last a life time doing bogging. but you will have to have some machining done to the motor for the crank and get it bored .030 over just another guestion do you run you rig in 4 wheel high or 4 wheel low? i run mine 4 wheel low and second gear and when the suction really starts to pull you in drop it in drive one and make the 4 bbls work

[ap72]

You can have a 383 that lasts a long time under bogging conditions if you don't live with the throttle burried and keep the compression and cam moderate. I would go with something liek a 268 cam and about 9:1 compression. It'll have plenty of torque and run on 87 octane- not to mention have a fairly long life as long as you don't get the cheap off cast crap.

[houston4x4]

well i run it in 4 wheel low actually.. and im not gonna be doing a bunch of bogging. i just want the power to be there when i actually need it i priced a 350 bare block last night on jegs. 680 bucks, anyone else have any recomendations if i do decide to go with the 383? i was thinking starting out at the bare block and just build the engine up then trade out the 350 thats in there right now and build that one to a 383 also.

[Slimpikins]

If you want some serious torque try finding a vortech 350 block out a 96-98 pickup at the salvage yard (they were factory roller) and stroke it.

Use a Comp Cams 276/282 hydrolic roller. You can save money on this because Instead of spending $600 on lifters you can get OE lifters from any parts store for around $200, But the cam costs nearly $300.

Use whatever heads you want. Vortechs are good too if you can find some that arent cracked for a bargin price, plus they out flow any other production head. You can probably get the block and the heads from the salvage yard (especially if you go to a u pull it salvage yard) for around $400. then all you need to spend money on is a 1 piece 383 crank and machine work.

Comp Cams Has an article on a Vortech 383 with the XE268 that produced 450hp 450ft-lbs of torque that had 9.6/1 compression and ran on pump gas.

[ap72]

For a low duration cam in a low RPM engine a roller offers minimal if any bennifits (some say it actaully reduces torque). The Vortec heads aren't a bad option but they require a Vortec valve train and intake. Never use just any heads you want. You'd be better spending money on heads than a stroker kit. For a low end torque monster of a 383 I would either go Vortec or with something liek a Dart Iron Eagle. Its relatively cheap and has good flow for the relatively small runner volume.

You can also just reuse the heads you have if you want to save some coin- but you'll probably give up about 30 ft*lbs.

One point that may be contested is that I recomend a Performer Manifold with EGR. SOme will argue that an RPM AirGap gives more power- and it does- but the performer (or the "Z28" manifold for that matter) will give better throttle response, fuel atomization, milage, and increased engine life- in this application I say that may be worth the 8hp on the top end.

[Slimpikins]

check out comp cams website and look at the dyno results of the extreme energy cams roller and non roller. both of these cams have the same duration at .050 see the difference.

Dyno Results
Camshaft Part # 12-242-2 Designation XE268H-10
Duration @ 0.006" 268 / 280 Duration @ 0.050" 224 / 230
Max Lift w/ 1.5RR 477 / .480 Lobe Separation 110
Lobe ID#'s 5443 / 5203 Intake Centerline 106
Engine Type Chevrolet 350 Small Block
Bore 4.040" Stroke 3.480"
Displacement 356 Compression 9.25:1
Heads Dart S/R Intake Edelbrock Performer
Carburetor Holley #3310 Vac. Sec. Exhaust 1 5/8" Headers
Max Torque 413 ft*lbs @ 3800 RPM Max Power 342 HP @ 5000 RPM
Manifold Vacuum 15.5" Hg @ 800 RPM & 17" Hg @ 1000 RPM w/ no load.


Dyno Results
Camshaft Part # 12-423-8 Designation XR276HR-10
Duration @ 0.006" 276 / 282 Duration @ 0.050" 224 / 230
Max Lift w/ 1.5RR .502 / .510 Lobe Separation 110
Lobe ID#'s 3314 / 3315 Intake Centerline 106
Engine Type Chevrolet 350 Small Block
Bore 4.040" Stroke 3.480"
Displacement 356 Compression 9.25:1
Heads Dart S/R Intake Edelbrock Performer
Carburetor Holley #3310 Vac. Sec. Exhaust 1 5/8" Headers
Max Torque 427 ft*lbs @ 3700 RPM Max Power 373 HP @ 5200 RPM
Manifold Vacuum 12" Hg @ 800 RPM & 14" Hg @ 1000 RPM w/ no load

[ap72]

notice the increase advertised duration on the HR cam- which should have faster ramp rates... and the lower manifold vacuum.... Perhaps its because its a BIGGER cam. That's like comparing a tangerine to an orange- yes they're both citrus fruits and look very close to the same, but one is still bigger- even if its slight.

I forget what the cut off is but its somewhere in the 260's or low 270's range... Anything less than that more often than not will do better on the street as a hydraulic cam... I don't know how it works, it just does.

[Slimpikins]

It doesnt necessarily have to have more duration. U look at the difference yourself. which one holds the valve open longer at .350 valve lift longer. thats where power and torque come from.

[ap72]

I understand your points, but the increase in duration aptly explains the power and vacuum charecteristics of the engine examples you provided. For serious street/strip cars you cannot beat a HR cam, but when you're not looking at large duration figures or high lifts the evidence is simply not there to support buying a roller cam. Your money would much be better spent on a set of high ratio rockers with a hydraulic cam.

[Slimpikins]

Point blank roller cams are more aggressive than a flat tappet (solid or not) your right though on one thing. Flat-tappet cams can lift the valves sooner. the only thing about that is they dont hold the valve open for as many degrees as a roller cam when you start looking at figures above .300 lift. If you have a set of heads that flow 280cfm at .650 lift and flow around 240cfm at .400 than which cam will make more power. Lets say both cams were a 292 with .600 valve lift. Which cam will hold the valve open longer at .400 lift No questions asked, you know that the roller cam does. Its because of its ability to hold the valve open longer at more lift that makes the roller cam more aggressive. Also there is less friction on a roller application and they tend to rev up very fast, and at high rpm you want as little friction as possible.

B U T, I have heard rumor that when it comes to 8000 RPM range the roller lifters are heavy enough that they can cause valve float. they have a fix for this problem but its expensive. How many people do you know that can still make power at 8000 RPM with a SBC? I know of a 327 that turned 7800 RPM, but thats the highest Ive seen as far as a normally aspirated engine.

[houston4x4]

well lets face it i wont be going near those rpms. ill more than likely stick below 4000 and thats a high side. i havnt decided what kind of cam exactly to go with yet. or crank for that matter.. ive heard alot about this company called eagle. so im looking into them really hard. ill prolly go with a cam made by comp cams just because they have been around and from what ive always been told they have great products. what im trying to do is learn as much as possible about the 383 stroker and everyone on here seems to have a pretty good knowledge about them. another thing someone might be able to tell me is im thinking about going with titanium roller rockers and rods. would this be a bad thing for this engine with the type of application im going to be useing it for? i mean im not gonna be going into mud every day all the time but i will want to go out and have fun in it if u know what i mean. lol