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Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
Not sure if this is the best forum to ask this, but as some background I'm building a 350 for my 85 Camaro. I bought a pair of remanufactured vortec heads for a reasonable price so I picked them up. I was recommended to run a comp cams 252H ( https://www.compcams.com/high-energy-206-206-hydraulic-flat-cam-for-chevrolet-small-block.html#tab2.tab2 ) cam with these heads, as I don't want to get new springs and I was told it would work great for these heads. I then went and got the recommended 1.52 magnum rockers ( https://www.compcams.com/rocker-arm-kits-chevy-v8-262-400-1-52-magnum-rockers-pushrods-guide-plates.html ) which came with the pushrods, guideplates etc. Now I now I need to install screw in studs, but I'm wary of which ones I need and how much I need to machine these. I want to do it myself (I can't afford a machine shop, and there are none in my area) however I can't find a very good tutorial on how I should go about this. Some people say there is no need to flatten the stud boss for guide plates, while others say you must. Other people say you shouldn't do it all because it screws up the valve train geometry, and you should go with self aligning rockers. I want to run these rockers though and I am 99% sure I need guide plates for them. If anyone else has vortec heads with guide plates and could share their 2 ¢ it would be greatly appreciated. Also this is my first engine build so yes I am a noob and yes I could have said something that makes no sense, and I would greatly appreciate it if you would correct me. Thanks
When I searched the web page you posted, the image did not show guide plates. Nor did it appear to have self guiding rockers. Can you verify?
Sorry for the confusion. They aren't SA rockers and the kit does come with guide plates specifically comp cams number 4808-8. The pictures aren't always accurate but the description says it comes with it, and they were in the box. Really my only question is do I need to mill the stud bosses and if so how much, and which bolt in studs do I need? I think there's a couple different sizes. I was told by someone at comp that I can run non self guiding rockers as long as I had guide plates installed but I never got any specifics from them.
Machining (in your case) is absolutely necessary.
Rather than ramble about what I did, I'll refer to this discussion over at Speed Talk. You'll find your answers there (and then some).
The short answer is .375" which accounts for the thickness of the guide plate plus the thickness of the integral jamb nut on the stud itself.
As for the rocker stud choice (and I'm familiar with ARP), choose the diameter that matches your rocker (3/8" is probably what's included in your kit) and the length appropriate. The kit looks to have rocker ***** and jam nuts so the shorter of the ARP choices should get the job done. If you were going to use poly-locks then the longer stud is used. I have part numbers stored in my PC but no access at this time. You can verify the length by measuring the stud height currently installed and adding .375" to it.
Hope that helps. If you can get past some of the blather at Speed Talk, you'll find some solid info.
The even shorter answer is, get self-aligning rockers instead of those, and don't mess with the studs at all.
That's probably not "the best" cam for the application at hand, for several reasons. First, it's not a roller; if your block supports the factory roller system, you should get one of that type instead. Second, if you do indeed intend to use a flat-tappet cam, you'll need lifters, too. Third, it's not a real good match to the properties of the heads; those heads have all this WONDERFUL intake flow (which is of course what makes them so much better than others), but the same sucky exhaust ports as any other SBC head, which means the cam needs to favor the exh side which that one doesn't.
IMO you could do yourself a favor by returning that stuff and kinda re-thinking this whole endeavor.
You MUST MUST MUST MUST MUST MUST MUST replace the valve springs if you install an aftermarket cam!!! I cannot stress this strongly enough. The stock Vortec springs aren't really adequate even for the stock Vortec cam, which is QUITE mild; and is TOTALLY inadequate for aftermarket "performance" cams of any kind, with their aggressive ramps.
With appropriate cam and rocker choices, screw-in studs aren't necessary. Instead of those rockers
If the motor is a roller (87-up) use this cam instead.https://www.compcams.com/xtreme-ener...oller-sbc.html The stock roller lifters are fine, if they're in good shape which you can inspect for yourself. If the motor isn't factory roller look at this one https://www.compcams.com/xtreme-ener...all-block.html and of course the lifters to match. In either case you can use the basic entry-level springs such as Comp 918. You can change the springs out yourself: you can "rent" the tool for free at your local parts store. In either case, if you want those ball-seat roller-tip rockers, get the self-aligning type. Push rods will vary depending on what lifter you end up with; with flat, you'll need 7.800" long, with rollers, they're shorter, probably 7.200" but that will depend on what lifters you end up with. No machining, no screw-in studs. You may however want to go to the Chevy dealer and get stock rocker nuts: the ones that Comp supplies are VERY hard and sometimes break.
All of that of course is assuming that your original cam choice is appropriate to begin with. That in turn would depend on your gears, converter, whether the motor will be carbed or FI, your intended usage (work truck, daily driver, your teen-age daughter to drive to school, Saturday night warrior, street/strip, oval track, etc.) without which we cannot begin to guess what "the right" cam would be for your build.
The even shorter answer is, get self-aligning rockers instead of those, and don't mess with the studs at all.
This would have been the obvious answer if the OP hadn't already had the parts in hand (which is my understanding).
I've had reasonable success with Vortecs in STOCK trim and cams up to .460", short duration and flat tappet. That said, the unforeseen can happen (at least with my short-sightedness) and that's bent valves from missed shifts and wiped out cam lobes for reasons attributed to poor maintenance and uninformed oil selection.
The even shorter answer is, get self-aligning rockers instead of those, and don't mess with the studs at all.
That's probably not "the best" cam for the application at hand, for several reasons. First, it's not a roller; if your block supports the factory roller system, you should get one of that type instead. Second, if you do indeed intend to use a flat-tappet cam, you'll need lifters, too. Third, it's not a real good match to the properties of the heads; those heads have all this WONDERFUL intake flow (which is of course what makes them so much better than others), but the same sucky exhaust ports as any other SBC head, which means the cam needs to favor the exh side which that one doesn't.
IMO you could do yourself a favor by returning that stuff and kinda re-thinking this whole endeavor.
You MUST MUST MUST MUST MUST MUST MUST replace the valve springs if you install an aftermarket cam!!! I cannot stress this strongly enough. The stock Vortec springs aren't really adequate even for the stock Vortec cam, which is QUITE mild; and is TOTALLY inadequate for aftermarket "performance" cams of any kind, with their aggressive ramps.
With appropriate cam and rocker choices, screw-in studs aren't necessary. Instead of those rockers
If the motor is a roller (87-up) use this cam instead.https://www.compcams.com/xtreme-ener...oller-sbc.html The stock roller lifters are fine, if they're in good shape which you can inspect for yourself. If the motor isn't factory roller look at this one https://www.compcams.com/xtreme-ener...all-block.html and of course the lifters to match. In either case you can use the basic entry-level springs such as Comp 918. You can change the springs out yourself: you can "rent" the tool for free at your local parts store. In either case, if you want those ball-seat roller-tip rockers, get the self-aligning type. Push rods will vary depending on what lifter you end up with; with flat, you'll need 7.800" long, with rollers, they're shorter, probably 7.200" but that will depend on what lifters you end up with. No machining, no screw-in studs. You may however want to go to the Chevy dealer and get stock rocker nuts: the ones that Comp supplies are VERY hard and sometimes break.
All of that of course is assuming that your original cam choice is appropriate to begin with. That in turn would depend on your gears, converter, whether the motor will be carbed or FI, your intended usage (work truck, daily driver, your teen-age daughter to drive to school, Saturday night warrior, street/strip, oval track, etc.) without which we cannot begin to guess what "the right" cam would be for your build.
Its an 84 block and I'm not gonna try and retrofit a roller setup. If I could I would have obviously gotten a roller. And the lift does not exceed the max these heads can get, and in fact, there's a guy on YouTube who almost has the same setup, same cam, vortec heads, but with different rockers and he's getting 320 hp. This isn't gonna be a drag car and I want to stick with this cam because its slightly above mild and I actually want to drive it around town so. I may consider getting self aligning rockers if it turns out to be too much of a pain, it's just they cost $$$ from what I can tell.
Machining (in your case) is absolutely necessary.
Rather than ramble about what I did, I'll refer to this discussion over at Speed Talk. You'll find your answers there (and then some).
The short answer is .375" which accounts for the thickness of the guide plate plus the thickness of the integral jamb nut on the stud itself.
As for the rocker stud choice (and I'm familiar with ARP), choose the diameter that matches your rocker (3/8" is probably what's included in your kit) and the length appropriate. The kit looks to have rocker ***** and jam nuts so the shorter of the ARP choices should get the job done. If you were going to use poly-locks then the longer stud is used. I have part numbers stored in my PC but no access at this time. You can verify the length by measuring the stud height currently installed and adding .375" to it.
Hope that helps. If you can get past some of the blather at Speed Talk, you'll find some solid info.
This is exactly what I was looking for, thanks. There's just so little info out there about this with conflicting opinions and such. I will definitely look into this
This is exactly what I was looking for, thanks. There's just so little info out there about this with conflicting opinions and such. I will definitely look into this
While there are cutters available for the DIY approach that part is easy enough. The difficult part is ensuring the tapped holes are perfectly perpendicular to the newly machined flat on the stud boss.
