Has anyone put the LT4 cam into an older 2 piece main-seal block? What's involved? I want to get some retro-fit hyd roller lifters and use this cam but I need some more explanation on how to do this. I want to use the Vortec heads. I have to shave the valve guides and enlarge the spring pocket. What I don't understand is the following statement from Chevy Hi-Performance:
Trim the ears off the production roller-cam thrust plate and use it as a
spacer BETWEEN the cam gear AND the block????? Then employ a thrust
button(understand this) to control cam endplay. This will require using
aftermarket hydraulic roller tappets(understand this), which are more expensive
than the factory hydraulic roller tappets. This way, you could use your
existing, older two-piece rear-main seal block.
Basically, I want to do the Oct 2001 article on the 400hp 350 engine with the older block. Thanks for your help,
Craig



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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com

 

Don't forget that you'll likely need a softer distributor gear.

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Vader
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"Click - Click - BOOM!"
Adobe Acrobat Reader

 

You could get what is nowadays referred to as a "retrofit" cam and not have to worry about any of the ethnic engineering. IMHO it isn't worth the trouble and risk of parts faliure, just so you can run the buzzword cam.

Distributor gear is the same: the buzzword cam, as well as most of the street roller hydraulics from the aftermarket, are similar in composition to stock cams; so stock dist gears are fine. That's what I've always used with hyd rollers, with exactly zero failures.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Icon,
I'm having trouble finding a cam similar to the LT4 in the aftermarket plus I forgot to mention this is a budget motor. The aftermarket cams are much more expensive and all the top end stuff to go with it.
Here are the specs for the LT4: I:279 E:287, @.050 tappet lift I:218, E:228 and with a 1.6 rocker max lift .525 I&E, LSA 112

The Comp cam XR276HR is I:276,E:282, @.050 tappet lift I:224,E:230 and with a 1.6 rocker .535I and .544exh. with a lsa 110deg. How much of a difference does the 110 vs 112 make?
Does this seem similar to you? According to compcams catalog the K-kit comes with the cam, cam button, and pushrods. That combo costs $759.00. The roller lifters cost $300. Whereas I can get the Hot cam kit(camshaft, self-aligning 1.6 roller rocker arm, retainers, valve springs, keepers, shims) for $475. See the difference.
Thanks for your input. Still weighing my options,

Craig

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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com

 

IIRC the LT4 HOT cam kit doesn't come with lifters or push rods(why should it? it's intended to go into motors that already have roller lifters) so you will have to buy those. In no case can you use the factory hydraulic roller lifters in an early block. So no matter what, you're going to be buying original style roller lifters, and also the roller-length push rods. That puts the prices a whole lot closer. Push rods = $40, cam button = $15. Those aren't where the money goes. The big-ticket items in the system are the cam, lifters, and rockers. Either way you go you'll have to buy all those things, plus the springs, retainers, keepers, etc.; and the button and push rods. It adds up.

The 2° difference in the lobe separation will make the LT4 cam have slightly less low-end torque and a little more high-end power, but will idle smoother with slightly higher vacuum. It's set up to favor a FI system. The Comp will have crisper throttle response and more bottom end, but idle a bit rougher. Most likely it will produce more overall "area under the curve" power, i.e. go faster, and with a carb, it's easy to tune for. I have its big brother the XR282HR in a 400 that was in my 83 until recently, as my daily driver.

Frankly, the difference in cost between the 2 is so slight, by the time you get to the end of the project it will be drowned in what you will spend on heads, short block, misc incidentals of all sorts, an intake manifold that will bolt to those heads, etc. You're not going to realistically build a "budget" roller motor if you have go out and buy all new roller components, because that stuff isn't cheap. Plus you're going to end up with about $700-750 in those heads alone, even if you leave the crap truck replacement valves in them, especially since for either of those cams you pretty much have to step up to screw-in studs. This is not going to be a cheap motor to build, although with either of those cams, it ought to run pretty hard.

To answer your earlier question about the retainer plate used as a spacer, the LT4 cam has the stepped nose for use with the retainer plate, and the cam gear for that type of cam is thinner where it fits against the block so that it leaves room to fit against the retainer plate instead. If you use that kind of gear with no plate, the cam will go into the block the extra distance equal to the thickness of the retainer plate. I believe the early (thicker) cam gear will not go onto the factor roller cam's nose properly, but I could be wrong about that. I'm going to have to talk to some of my friends at the major cam companies and find that out some one of these days. It's a real shame that when the factory decided to "invent" roller cams they didn't just duplicate what the rest of the world had been doing for decades; instead they came up with that bizarre, unnecessary assortment of way too many parts that's not compatible with anything else, for what reason I can't begin to guess. If they had taken the sensible route, this sort of thing would be a whole lot easier.

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"So many Mustangs, so little time..."
ICON Motorsports