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eating my words

17K views 74 replies 17 participants last post by  ap72 
#1 ·
Well, if all goes well tonight I'll be picking up an LT1 engine even after I swore I'd never touch a sbc again.

Looking for input on what people would recomend for a good cam regrind, I know it depends on the vendor but I'm thinking something around 220/220 on a 108lsa?

It'll be pretty basic, mild port job, shorty headers, milled heads. Keeping it cheap and simple.

I'm worried 220/220 on a 108 may be too much for a 2000rpm cruise speed? Any problems with surging with a cruise speed that low? I'd like to keep peak power to around 5500-5700, may go a little smaller on duration.

I'd appreciate the veterans input.
 
#4 ·
Put a Hot Cam kit in my friends '94 Z28 LT1 a few years back, it was streetable, Rumpity idle, decent driving characteristics. I'd check the optispark out before you put it in anything and replace the guts, & cap with an aftermarket part that has the downward facing vent tube. From the factory some of them faced up, collects moisture. Optispark is behind the water pump. Everything else was decent enough on it, if you pull the heads take it easy on the crossover coolant line in the back. It had rigid style fittings that suck to work with in the car (at least the Camaro). With a good tune that car ran hard. Sounded real nice I thought. That's about all I remember from that thing.
 
#7 ·
If it's any help I run:
Lunati street master 275, 225@.050, .477" lift, 108 lsa. IO:8.5B IC:36.5A. EO:44.5B EC:0.5A
My compression is about 9.6:1. Iron heads. It pull 15"hg in park, works decent (not PERFECT) with power brakes, and is done around 55-5800 rpm depending on how it's installed. I have a 2600 stall, but the converter is tight for running on the street. 3.27 rear gear, 26" tire. I dot have any issues driving it at low rpm. The idle is noticeable but not ridiculous. Idles best around 1100 in park.
 
#10 ·
IMO if your geared to have a cruising speed of 2000rpm your shooting yourself in the foot with a 108, its going to be "peaky" and narrow, if its a strip only build with a narrow operating range then it makes sense. Your 2000rpm cruise tells me its over driven or way under geared, the car will be faster with a wider power band using a 110-112 LSA
The duration is fine at high teens or low 220's with a sub 470 and will make plenty of low end.
 
#11 ·
I was concerned with the 108 and lugging it at lower rpm, of all the **** I've done when it came to large overlap I always had gear to go with it. This is overdriven so cruise will be low. The 108 is pretty narrow, the idea was to help crutch the near stock intake port with good exhaust flow, same as with any other narrow lsa. I did end up getting the engine and it's out in my trailer right now, it'll get a little loving but nothing overkill. I may go smaller on the intake duration, this will be a street cruiser and see some miles so decent mileage will be nice. I've been looking at the lt4 hot cam results and I may go with something like that but on a narrower lsa so it hits hard in the mid range. With stock components in the lower end I don't want to rev this much. I don't need to prove anything with it just want a fun car, I already know any modern muscle car will kick it's ***.
 
#12 ·
The problem is going to be with the Optispark, its likely going to have to be custom ground to get anything under a 112 and still have the dowel to drive the optispark. The hotcam will do what you want and having it custom ground with a 110lsa will move the power band down slightly. If its strictly a budget build sorta deal and you wanna stick with an off the shelf grind then look at a Lunati 20080660, its 213/219 on a 112 LSA with 447/471
Its going to be all done by 5500 and have a nice mid range punch
 
#15 ·
The Hot cam is kinda old tech,but,it is an almost guaranteed 400 HP with the support behind it.The Lunati Bygddy suggested would do well also.The Hot Cam worx better with a lil higher stall behind it than stock.They say it can be a PITA to tune,but,worth the effort.
 
#17 ·
what icl are you considering?
without talking about specific support equipment,just the cam specs,220º and 108º lda is a very mild cam with what looks like a perky mid range power band.
My cam is 108º icl and 108º lda with 256º/264º @ .050 duration,and I "can" lope along at 60 mph in 5th gear(2000 rpm)my cam peaks at 6500 rpm in a 434. my engine will buck a little at 1700 rpm but still accelerate smoothly, even in 5th gear.
If you choose 220º with 108º separation, I dont see any problems if all the other parts match.
mileage should be ok.
this cam is something I would use in a moderately heavy touring car
 
#18 · (Edited by Moderator)
**************

Back on track, I have a throttle body that I blended and smoothed over, probably not worth a lot but I'll be going with that and port matched intake (all the way up the runners since these are short) and shorty headers. I would probably be using factory exhaust manifolds if the guy still had them but they weren't included, may stil go with ones off of ebay depending on what I can find cheap.

I'm not at all concerned with peak power numbers, I just want a really strong midrange, hence the early power peak goals and tighter LSA- a strong torque band from 2500-4500 would be ideal as that is where I will be doing most of my driving. I may back it down to something like a 215/215.

This dyno sheet shows something close to what I would like but their test mule engine is a bit different, COMP Cams® - Xtreme Energy 264 Hydraulic Roller, Camshaft Part # 12-412-8 Dyno Sheet.

Personally I feel the LT4 hot cam has too much exhaust duration, anyone know of a similar combo on a single pattern cam?
 
#20 ·
I used them for a custom cam years ago before they were bought out, NM just checked the site, that's the other Elgin. I'll contact them about a regrind. I'll probably give it to Mike Jones if his price is close, he seems to be the best and an all around good guy. He'll probably have the final say so in the lobe selection but as of now I'm leaning 215/220ish on a 108 LSA, with a lift that I can use drop in springs for- keeping it low budget.

Since I'm milling the heads .030" I'd like to not have to swap pushrods either, but that's probably asking for a bit too much.
 
#22 ·
Getting this thread back on track, some posts were edited, some removed.

I'm also interested what the reason is for regrinding and existing cam, unless you live next door to the grinder, seems shipping back and forth would negate any benefit over buying new, unless you were doing a batch of them. :confused:
 
#23 ·
I've done regrinds already with a few other companies and it was about half the cost total (shipped both ways) of buying a new one, shipping each way really isn't that expensive.


And F'bird I've considered that cam and may go with it when I compare the cost to regrind VS the cost of a take out cam off ebay. I'm wanting something with a smaller duration split but as always "cash is king" if its only 20-40 difference though I'll be getting regrind, any more and I reckon I'll be running the cam you suggested.

Today I've spent some time going over what needs to be done/options for running this with megasquirt, I already have a couple MS units and I'd like to stay with it since I'm comfortable with the tuning now. It looks like the IAC will be the only hurdle I have- I may try to run without it and if need be upgrade to the MS2 daughter board after I have it all installed.
 
#26 ·
I've been thinkin bout using that Comp 264 cam too.It looks like it would make a decent street cam.You shouldn't have any problems witha 2000 rpm cruise.If you use the 1.6's,you'll be a tad over .500 tho.I haven't used 1,but,i've heard & read complaints about the ZZ cams being pretty soggy on the lower end.The newer versions may be better tho.
 
#30 ·
I'm a big fan of Isky cams and I'm running the 270 Mega Cam hydraulic in my 327. It's almost exactly the specs you originally posted at 221/221 108 LSA .465" lift. I love it, and it works. If you wanted a little less cam for a milder build then the 264 Mega is a little less at 214/214 108 LSA, and .450" lift. The 270 will work with any trans, but is a little higher idle. The 264 will work with any trans and any converter, no matter how small.
 
#31 ·
Well, there's a reason I got the engine cheap. The crank is toast and one rod as well. It spun the **** out of a bearing. As such my 302 rotating assembly will be getting dropped in. Damn glad I have a stock pile full of parts. This thing will only cost me the cost of hot tank and cam bearings to get the short block done. Cam and maybe pushrods for the valve train. And gaskets. Not bad for accumulating **** off eBay and Craigslist.
 
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