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Discussion Starter · #1 · (Edited)
Hey guys. I have the 420hp Blueprint 383
BluePrint 383 S/B Chevy Crate Engine - Speedway Motors, America's Oldest Speed Shop

And the valve lash has been coming out of wack lately, and its starting to become a pain. So instead of working with the cheap parts this came with, I've decided to put a new cam, pushrods, roller rockers, guide plates, etc on it. It came without guide plates, and stamped vortech style rocker arms.

My question is, what do I need to go with a roller cam, and what should I get? I've only ever ran flat tappet cams, and I've decided to spend about $2000 or so to spruce this motor up, and make it as strong as I can. But I want to be able to do the most I can without pulling the motor. Or should I just get another flat tappet? Please check the link provided above to check out the parts the motor already has.

I run it in my 1970 Monte Carlo with a fiberglass front clip, hood, front bumper, a TCI TH350, 3500 RPM stall, a 12 bolt and 4.56's. I'm just getting it all set up for the strip as close as I can, and then this whole problem arose.

I'm all for a new cam, valvetrain and intake, but don't know what to get, what I need, what would be best, etc. I run a 750 Holley double pumper, and am just curious what cam/intake combo etc I should run to be as competitive as I can at the strip, without sacrificing ALL of the car's streetability.

Thanks in advance. :D
 

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Discussion Starter · #2 ·
Oh, and for some eyecandy heres the car a few months ago prior to the fiberglass, seats, harness belts, etc. 403472_10151866652620425_582012541_n.jpg
 

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The easiest thing would be to stay with a flat tappet cam, but you need to locate the source of your valve lash problems first. If you want to go with a roller (which is a great choice if you can afford it) I think it would be much easier to buy a complete kit, cam, lifters, springs, retainers from one of the major manufacturers. Your heads should have screw in studs so guideplates will be easy but you'll have to use hardened push rods and non self aligning rocket arms. You'll also have to be mindful of guide to retainer clearence and valve to piston as well. Love those old montes btw
 

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Problem #1, you don't set lash on a hydraulic cam!

Your lash can't vary as you shouldn't have any! You should have preload, about 1/4 turn.

With that being said you may not want to change anything at this point. You'll want to shift it around 6,000 rpm on the track.
 

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Cam shafts

Checkout this cam kit at Comp Cams: COMP Cams: Xtreme Energy™ XR288HR: Cam & Kit. Be sure and call them to make sure the push rods come with with this kit. Add a set of Scorpion Roller Rockers too. Check the stud size and make sure they are screw in for the rockers, if they are 3/8 I would have them changed to 7/16 studs. According to the dyno on Comp cams website, with heads ported, victor jr intake, 750 HP carb this cam will make about 484.7 HP at 6500rpms and 445.4 lbs. of torque at 5000 rpms. With heads as is and dual plane intake this same cam puts out 392.3 hp at 6000 and 401 lbs of torque at 4500 rpms. A hyd. flat tappet cam similar to yours made 383.8 hp at 5500 rpms and 415.3 lbs of torque at 4000 rpms.
 

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I'm a little confused. I've never seen a pair of aftermarket aluminum heads that didn't come stock with guideplates and screw in studs? Are you saying this engine came without either?
 

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Discussion Starter · #8 ·
Your lash can't vary as you shouldn't have any! You should have preload, about 1/4 turn.
Sorry for any confusion, but that's what I've been doing. I set the preload and go another quarter turn.

I switched the cheap chinese nuts with stock nuts and they seem to hold better, but I'm still worried that all the tinkering etc might have affected the cam.
 

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You didn't mess anything up by tinkering. You can get a set of positive locking nuts that will hold tight if the ones you have don't work. You can also adjust preload while the engine is idling if a few of them are ticking.
 

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Not sure what brand of heads Speedway is using on those engines, but you deinitely don't want to run any aluminum head without guideplates! I'm shocked they even sell an engine with those heads and no guideplates. Wonder if they also don't use hardened pushrods?
 

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Discussion Starter · #12 ·
Yea, I thought the whole point of self aligning rocker arms was to not need guide plates..Anyway, I'm not sure if the valvetrain is actually changing its configuration every time I mess with it, or what the deal is, but after about 2 minutes of quiet normal idle, it starts clacking, RPM changes, etc.
 

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valve train

I would buy a new set of ARP screw-in studs and a set of poly locks. That would take care of the rocker arms loosing. If you still have some noise then go with the Hyd. roller cam kit, single plane intake with a Holley HP 750. I would also check the aluminum heads for the manufacturer. Remember porting the heads adds 70 HP according to the dyno on Comp Cams CamQuest.
 

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Not sure what brand of heads Speedway is using on those engines, but you deinitely don't want to run any aluminum head without guideplates! I'm shocked they even sell an engine with those heads and no guideplates. Wonder if they also don't use hardened pushrods?
The heads come from Blueprint, no info on who the casting is done buy, but its designed to use the self aligning rockers, so it doesnt need guide plates or hardened push rods. Keeps Blueprints profit margin up.

Anybody know how Blueprint managed to get the contract to supply "crate" motors to Summit, Jegs, Speedway,...
 
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