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Old 02-01-2010, 12:35 AM
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Suggestions or problems with this 350 build?

Okay, I am a definite newbie but willing to learn, here's the setup, questions at the end(thanks for any help!!):

I have been reading a TON on this forum and thankfully was able to answer almost all my questions without posting and here's what I came up with for my budget.

Got a 73 corvette, rebuilt 700R4 tran, rear axle 3.36
Engine was already in the car and running, but want to add performance- heads/rockers/manifold/cam will be new.
Not real interested in going to the track, rather have good driveability but still be fairly agressive(on pump gas).

350 4 bolt casting 14010207 , 4.03
RHS-12410 Vortec heads 64/170cc (2.02/1.6 valves)
Edel-7516 performer RPM air gap
Comp-1302 pro magnum full roller 1.6
Holley-4160 carb 600cfm
Hedman-68300 small tubes
Comp-cam, probably XE262, but have been considering XE268
pistons-unknown!!(about to find out)
head gaskets-undecided until I find out what the pistons are!


Questions:

Is this casting going to handle what I'm doing?? Right now there are some real awful 76cc heads in there. I would like to be making low 400s torque in the low range and low 400s hp at the top(maybe ~5500-6000 rpms?).

Are the 2.02/1.6 valves on the RHS vortec heads a waste of time or should I stick with the 1.94/1.5s?

Is the XE262 perhaps too small? Would I be sacrificing a ton of top end hp or just a little? XE268 or even XE274 worth considering?

Any other comments or concerns or needed info?

Please, be gentle.

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Last edited by sabbath; 02-01-2010 at 01:02 AM.
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Old 02-01-2010, 01:22 AM
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Shoot for 9.5Cr., 268H Cam w/218/218Dur.-.454/.454Lift or other cams below, 1.94"/1.50" Valves, .040"-.045" Quench/Piston to Head Clearance. RPM or Performer Intake, the AirGap is very cold natured not cool weather friendly & Corvettes don't have alot of hood clearance either.
The larger valves wouldn't be needed with a cam that small.
Using Comp's CamQuest>> http://compcams.com/camquest/default.asp
12-210-2/268H--- 1500-5500rpm
365HP@5000rpm
415ft/lbs TQ@4000rpm

12-238-2/XE262H---1300-5600rpm
367HP @5000rpm
418ft/lbs TQ@4000rpm

12-242-2/XE268--- 1600-5800rpm
380HP @5500rpm
414TQ @4000rpm

These aren't super accurate but give an close estimate.

Last edited by SSedan64; 02-01-2010 at 02:12 AM.
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Old 02-01-2010, 01:28 AM
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I am not sure how much lift the RHS heads can handle but the 262xe is a .462/.470 lift with 1.5 rockers. I think the 262 cam is would work well with your of trans and highway gears. It isn't got to be anywhere near 400hp. It could be around the 300hp neighborhood. You will have torque. The 274xe cam will definitly need a loose convertor.
The 262 cam don't have the hotrod rumpy rump idle but can still doesn't sound 100% stock. The 268 cam is noticable. check out youtube

Unless you have plans later to use the heads on a MUCH more aggressive engine down the road 1.94/1.5 valves will work just fine.

You need to decide what you are going to build around. Most will tell you to pick a cam and build around it. If you don't want to change your gears you limit your cam choices.

A 4 bolt sbc will handle your build just fine.
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Old 02-01-2010, 02:14 AM
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Thanks guys, even more to think about.

-Hood clearance: yes, I was planning on a low profile air cleaner to deal with that

-manifold: well I definitely wouldn't be driving it in the winter, also there is a high probability I will be moving to a warmer climate so I want to be flexible. Is that the only reason not to go with the air gaps?

-lift, the RHS vortecs are rated up to 0.560 so I should be fine there

-cams: yea I was listening to youtubes earlier, the 268s are nice but I think I'd be happy with the 262 as well.

-valves: I was considering the future, maybe a 383upgrade or 400 but... 'bird in the hand' I probably shouldn't worry about it lol... will 2.02s HURT me much?


Thanks!
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Old 02-01-2010, 02:15 AM
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Also, hp- what is the main thing holding me back?

Last edited by sabbath; 02-01-2010 at 04:22 AM.
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Old 02-01-2010, 02:20 AM
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With the 700R4's 3.06 1st gear you should have good launch/take off.
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Old 02-01-2010, 02:24 AM
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Current Condition

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Old 02-01-2010, 02:28 AM
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The AirGap's do fairly well above 50-55deg air temp. The Vortec style heads don't have an exhaust/heat crossover so that makes it worse with the Airgap. I not sure you'd have clearance even with the low profile cleaner.
The 2.02"'s would help above .500" valve lift.
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Old 02-01-2010, 02:34 AM
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Is this where you were looking for the RHS's?>> http://www.competitionproducts.com/C...products/1262/
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Old 02-01-2010, 02:48 AM
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Yes that is what I ordered, assembled. Great price! I think I found that site in another post here.

Well that's bad news about the clearance...guess I will have to double check everything. Don't really want to incur hood chopping expenses.

Going to bed now..
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Old 02-01-2010, 04:05 AM
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Well now you guys have got me thinking..

Maybe I would be better served with a Lunati 60103? I had my eye on that before.
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Old 02-01-2010, 07:59 AM
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Running the XE or VooDoo line of cams IMO is taking an unneeded risk for little reward. These agressive cams do not pick up that much power over the less agressive ones and have a much higher failure rate. If you want an agressive profile then go roller or solid wth EDM'd lifters. For a hot street daily driver I would go with something like the 268Mega from Isky with 1.6 roller rockers. With an RPM manifold and solid assembly/tuning you could probably come very close to reaching your 400hp goal, and exceed your tq goal.

Assuming you're runnig a stock stall that's about as large as I would go.

If you're not going to the track why worry about pushing things to their limit and risking longevity?

Last edited by ap72; 02-01-2010 at 09:47 AM.
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Old 02-01-2010, 08:04 AM
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Quote:
Originally Posted by sabbath
Well now you guys have got me thinking..

Maybe I would be better served with a Lunati 60103? I had my eye on that before.
glad to see you went with the RHS vortecs that i recommended, i see that you are looking at both the comp xtreme energy line, and the lunati voodoo line, they are both very nice and agressive hydraulic flat tappit cam lines but i also saw that you are planning on running 1.6 rockers with them, i wouldn't advise that, these line of cams have a very agressive ramp rate, really about as high as they can handle and adding the 1.6 rockers with increase incrase the ratio of which the valves open, ie; the valves will open and close even faster cause the are opening even farther in the same amount of time, i would seriously suggest going with the 1.5 rockers with either of these to cam lines, you wont loose anything noticeable out of the engine.

the comment about nothing close to 400hp but maybe 300hp is off, either one of these combos will produce over 340hp, those cam quest numbers are slightly inflated but not too far, take about 5% off those numbers and that is about what you should end up with, if you are willing to send the RHS heads to a machine shop (you should anyway, it's not advised to put a pair on straight out of the box) have them clean up the casting a bit and do some bowl blending, it wont cost you too much and it will be worth the extra expense.

i personally like the two 268 cams (both the XE and the Voodoo) it will sound nasty, (if you go with the voodoo i would go with the 2.02 valves as they are very close to .500" but you dont need them, it wont really hurt either way, as they use the same casting/ measurements for both the 1.94 and the 2.02's but the seats are just cut differently, so you really wouldn't have any velocity difference between the two of the, and there may be a VERY small amount of flow difference between them.

the air gap intake is not worth the extra money, they have done dyno tests with both RPM and the RPM air gap, and there is next to no difference, if i remember correctly they actually did better by notching the intake bore seperator and adding a 1" spacer. good luck keep us posted
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Old 02-01-2010, 08:10 AM
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One comment regarding 2.02" vs. 1.94" intake valves.

If the intake port is left as it was with the 1.94" valve and only the bowl opened up to accommodate the valve seat and there's just a smoothed transition from the bottom angle into the bowl, the 2.02" valve's larger circumference will allow more early lift flow. It's when the entire port is opened up to provide more CFM (and less velocity) that low lift flow and performance suffers, IMO.

There may well be some loss at some point, but the overall flow can be better on average, and low lift need not be made worse for having a larger valve. But then, much of the reason most people go w/a larger valve (upper RPM flow) is negated.
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Old 02-01-2010, 08:11 AM
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Quote:
Originally Posted by ap72
Running the XE or VooDoo line of cams IMO is taking an unneeded risk for little reward. These agressive cams do not pick up that much power over the less agressive ones and have a much higher failure rate. If you want an agressive profile then go roller or solid wth EDM'd lifters. For a hot street daily driver I would go with something like the 268Mega from Isky.

Assuming you're runnig a stock stall that's about as large as I would go.

If you're not going to the track why worry about pushing things to their limit and risking longevity?
i have also heard this, i thought about using the XE284 but decided it would be better to go with hwrd's solid and their direct lube lifters. the voodoo line tends to be a little more agressive than the xtreme energy, i know that their ramp rates are in question, but i've heard plently of people using them as well
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