got my malibu back... couple Q's

[cutlass389]

First off, I think that 4k stall is going to be a little too high. It's a little too high for street driving and if you insist on vortec heads, they are all done at 5600 which leaves you a narrow power band of 4000-5600. I run vortecs and use a 3000 convertor. Although it isn't street driven, it gives me a 3000-5600 power band which encompasses the torque peak to horsepower peak range of most normal(midrange) cams. Speaking of which, I'm using the Hot cam(roller) with 1.5 rockers and beehive springs(26915's as the 918's could pull the studs) which specs at 218*-228* .492 lift on a 112 much like a nitrous cam. I also run a 7.5 rear with slicks but would caution that it needs a good bit of upgrading to survive. I 60' around 1.60 for four years now but that's with Moser 28 spline axles, a stronger 28 spline posi with machined case(not cast) no spider gears, and a support cover. Also have the car down to 2950 lbs. The less it weighs the longer the 7.5(or any rear) will last. This is good for low 12's/very high 11's depending on weather.

 

[360demonRT]

so the 4k is to high.... i guess that makes sense. i just know several people that drive them on the street (camaros and mustangs) but, i guess they arent running a production head either now that i think about it. thanks for the imput. i might back that on down to a 3k. do you know what the curb weight is on a 81 malibu v6 car? iron headed 350/th350, bench interior, no heat/air box? also do you have a video of your car idling and at the track? i'd just like to see what the cam sounds like. the only reason i'm insistant on the vortech heads is because i'm right next door to broke. i'd love to have even some cheap aluminum heads, but thats 5-600 more than vortechs. with this car i'd be happy to run high 12s right now. thanks man

 

[cutlass389]

I'm not sure of the stock weight, probaby 3200-3500. No vids, sorry. Mine idles with 18" of vacuum, very smooth but this is in a 389 inch motor so it'll act a little smaller than in a 355. Vortec heads are the best production heads from GM and I'm very impressed with their torque production. Everyone talks horsepower but torque gets ya' goin', hp keeps ya' goin'. Just remember to match all your components to the same rpm range. Vortecs work well from 2000-5600. A huge cam or radical gears are better matched to high flowing aftermarket heads etc. I've even got a dual plane manifold as I shift at 5200-5500.

 

[Doober]

I'm hoping to be capable of 12s (even if it's 12.99) with a good carburetor tune and my current setup (9:1 350, Comp XE268H, stock Vortecs, GMPP intake, Edelbrock 1405, 2.29s with a 3.50:1 1st gear Saginaw).

 

[360demonRT]

same with me doober.. praying for 12's lol. all the magazine articles testing the vortecs seem to rave about the rpm airgap... i'm gonna try to get my hands on one of them. should do fine. cam quest seems to think (i think its full of sh*t half the time lol) that with a heavier vehicle with 3000rpm stall converters, with L31 vortech heads(that what i'm supposed to select?), a highflow dual plane, and large tube headers with mufflers that the comp 286H (hyd. flat tappet) will make 404hp@6krpm and 405ftlb@4krpm. does this sound about right... seems to be about dead on with most of the magazine articles? may try to pick up one of those cams to go with the rest of my combo. says it works good with 9.1 compression and 3kplus stalls. seems dead on with what i need. got a 110lsa too, so if i hang on to the n2o it should be able to take a hit of that too. comments?


here's the link to the cam and the specs.

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=80&sb=2

 

[cutlass389]

I 'm no genius but I don't think that cam is well suited to vortec heads. EVERY cam GM uses with vortecs has 10 degrees more exhaust duration than intake because they don't flow that good on the exhaust side. Also, 236* is a little much for them unless it's going to be a max effort race setup. I would look at the Thumpr(227-241 on a 107) or something in the XE series between the 268 and 282. The program said it'll make max. hp at 6000 but vortecs cannot make MORE hp above 5600 so that tells me that the 236 is a bit too much. If you must use giggle gas, I would look at blower/nitrous type cams with wider LSA's. Do you know if it's gonna' be flat or roller yet? You will definitely need a split pattern with vortecs regardless. As far as twelves, gettin' out of the hole has the biggest influence.

 

[360demonRT]

i do seem to remember something about split duration now that you bring that back up. this isnt gonna be a max track car... but i want it to haul some serious balls. i'm not dead set on the nitrous... matter of fact its up for sale on several sites. i'm trying to get something that will run damn near as good as possible off the bottle, but still not detonate if i keep it. and i think i've about decided to just use a non roller hyd. hydrollers are flippin expensive, that and i may be able to get a motor thats not set up for roller stupid cheap real soon (fiance's uncle has one laying around)

 

[cutlass389]

The "Hot" cam from GM is about the cheapest hyd. roller out there. Now you know why I've got one. 8) If I don't custom order my next cam(230-241 on a 104 LSA), I'm seriously considering the Thumpr. 227-241 on a 107 LSA is almost tailor made for vortecs. I almost forgot, from what I've read about the RPM manifolds, the airgap is more of a gimmick as it doesn't make any more power than the much less expensive Performer RPM non airgap.

 

[360demonRT]

found it, didnt know they made on in a non roller. just over 200 for cam/lifters... sounds completely wicked (youtube lol)

 

[cutlass389]

If you go non-roller be careful about oil selection and especially the break-in procedure. Ask Comp or any cam company rep for recommendations as the ZDDP content is down across the board which is crucial to flat tappet cams. Mine is off the street which is why I'm considering a 104 LSA. The 107 LSA of the Thumpr should make for a strong torque curve on a naturally aspirated motor but is spread enough to allow acceptable street manners if one doesn't get carried away with the duration.