Help with cam selection

[86Cutlass383SR]

I need some help choosing a cam for my 383 with EFI. I hope you guys can give me some ideas and guidance.

My main question is would the Comp XFI 280 cam hyd roller (retro-fit for my block) would be a good choice for a daily-driver or should I step down to a custom 224*/230* cam. The Comp XFI 280 cam has specs of 230*/236* .576"/.570" (with the recommended 1.6 rockers) on a 113* LSA. I would be running 1.5 rockers (because that's what I have for now) which would give me .540"/.534" lift. The custom 224*/230* cam would probably be ground on a 112* LSA. Basically an XE XR276HR on a 112* instead of the 110*LSA. I've also thought about maybe using an XE XR282HR of 230*/236* .502"/.510" on a 112* LSA with some 1.6 rockers which would pump up the lift to .535"/.544".

I'm rebuilding my 383 for use in a true daily driver. T56 and either 3.42 or 3.73 rear gears. I'm looking for any/all creative ideas, suggestions, and thoughts. I'll outline what I've got below. The cam is the only item I don't yet have.

383 2 pc RMS, KB hyper 12cc reverse dome pistons (4.040" 385 actual), 5.7 Scat rods and 9000 series crank. After engine mock-up, I plan on having the block zero-decked to my rotating assembly. With the recommended 1003 Fel-Pro head gasket at .041" comp thickness and zero deck my compression comes out to a calculated 10.04-1.

Induction will be Accel SuperRam (unported) with Holley 58mm t.b., Holley AFPR, 30# SVO injectors, and my choice of either TPIS Big Mouth or Accel bases (I have both - best?). 89 MAF with the '165 ECM.

Heads are older non-Elminator AFR 190's (unported) of about 66cc chambers and the AFR valves. 26120 beehive valve springs will be used instead of the 26918 beehives because of the larger dia spring pocket of the AFR heads. According to Comp, spring specs are as listed: seat press 155# @ 1.880" open press 377# @ 1.280" with .590" max lift. This is the big-block hyd roller valvespring. I also have the matching titanium retainers along with the AFR rev kit. These valvesprings are over and above what Comp recommends for the XFI 280 cam. I got a killer deal on them. I also have the Comp Pro Magnum 1.5 3/8" roller rockers. I may jump to a 7/16" 1.6 rockers in the near future.

My calculated DCR with the XFI 280 would be about 7.8-1. I know this is a little lower than most people run but I'm looking at the times I may have to run the lower octane fuel. Dropping down to the 224/230 cam would increase my DCR to about 8-1. Would this be too high to run the occasional tank of 80 something octane gas?

Is the XFI 280 too big for a DD 383 as far as reliability and low (to mid?) 20's mpg's?

I will be having PCMforless burn me a start-up chip for this combo until I learn how and what to burn my own chips. I have what I need to burn chips but lack the knowledge as of yet. PCMforless has already said burning a chip for the 230/236 cam would be no problem.

I know this is rather long but I've tried to include all information. Please give me some ideas. Any guesses on possible HP/torque?

Thanks to all

 

[86Cutlass383SR]

Just a bit of added info on what I'm looking for.

I had for awhile a 69 Camaro 350 4 speed with a 230* hyd cam on a 106* LSA so I do like a bit of lope. I know tuning has a lot to do with gas mileage but I'd also like to pull at least 20 MPG, and lots of overlap and MPG don't go hand-in-hand. I am looking for a bit of compromise in the lope of my fuel injected engine but then again, I'm not looking for 30 mpg either. A decent street machine type lope with a fair mpg, too. I know it can be gone, I just don't know what limits to stop at.

I'm rambling, I'll shut up now...

 

[cutlass389]

Lope and FI generally don't go together. That's why the wide(112-117) LSA's. My understanding is that a computer sees lope(overlap) as a vacuum leak/problem and tries to compensate for it. Overlap puts more unburned fuel into the exhaust, then an O2 sensor "sees" a rich situation and pulls back on the fuel. There may be newer ways to tune around this but that's how it used to be. If it's truly a daily driver only then you may not need so much duration which will help in the tuning.

 

[86Cutlass383SR]

I emailed PCMforless.com about burning a chip for a 230/236 110 cam and they replied "no problem". A few of the guys on Thirdgen.org are running even bigger cams, some on the order of 235 - 245 duration range on 109 LSA. Granted their tuning skills are much better than mine and they are not daily drivers.

I posted the same question there and got a few replies but I thought I'd toss out the same question here and on a couple other boards to get a general consensus.

I've decided that a 230/236 on 112 LSA cam is *probably* a little bigger than I need. I'm no engine expert si I was hoping that someone here had a simular setup that could give some feedback. Even getting a cam recommendation from the same company has resulted in totally differant recommendations. One guy said I'd need a 210/218 cam (in a 383!!??) and the next guy wanted me to run a 236/242 cam (in a daily-driven street car...).

I was just hoping someone had some experience with something a little bit more middle ground than those two extremes.

 

[cutlass389]

I've got a 389" although it's carbed. It's got the GM Hot cam in it and pulls 18" of vacuum. I shift at 5200(racing) but it'll go to 5500 without nosing over. Used to drive it on the street and it was very well behaved and no power brake problems. Idles at 700 rpms in gear. It specs at 218* intake-228* exhaust with .492 lift on a 112 LSA. The different recommends are probably due to someone doing the nudge, nudge, wink, wink thing about the "it's gonna be only a daily driver" part of the story. You need to be honest with yourself about intended usage now and down the road.

 

[86Cutlass383SR]

The cam I had in it before it needed a rebuild was a custom version of the XR270HR. The specs on mine was close to the GM Hot Cam only mine was at 218*/224* .495"/.502" with 1.5's but mine was on a 112* LSA. It was a nice cam but just seemed kinda tame and mild for a 383 to me. I'm just not sure if I want to jump to a 224/230 or try the 230/236 versionof the XE series. I thought about the XFI series from Comp Cams but I've heard they were fairly hard on valvesprings for a true daily driver.

 

[cutlass389]

"Tame and mild" is going to be easier to tune on a EFI setup IMHO. Could probably go one more step since it's a 383.