Engine Mods Outrageous Builds, High-Horsepower Modifications, strokers, and big cams for the Corvette

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Old Jul 20, 2001 | 03:32 PM
  #41  
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Let me walk through these topics:

I did indeed use a 1206 FelPro, I am pulling this combo as we speak. I will reemphasize that the heads were angle milled, which effectively rolls the heads to the outside of the engine. This is part of the reason that the 1206 works. Also to note, part of the print o seal does show, but the units seal. One item to note on factory L-98 heads you have to machine into the valve cover rail to allow them to sit flush (easy mod). I am currently using the 1206 FelPro with factory L-98 heads.

The SR with the base was flowed and the unit delivered 264cfm. This was enough to match the heads that were on the motor at the time. The base is mucho ported (i.e. remember 1206 FelPro), but the runners are moderately massaged, while the box is heavily radiused into the runners. I spent some time on the box trying to get it right. Never flowed the base or runners by themselves.

Flow numbers:
190 AFR/TPIS 210 AFR CP
.200 129/107 138/112
.300 193/155 200/155
.400 242/178 249/192
.500 258/192 278/209
.550 261/195 284/215
.600 288/221
.650 295/227

Basically when the 190 goes flat, the 220 continues to pull more flow. The good thing is the low lift numbers between the 190s and the 210s. That is where the valve spends the majority of its time, and these heads should really fill the cylinders. As a side note, the TPIS CNC program on the AFR heads did not appear any better than the CNC program by AFR. Also, a properly reworked L-98 ('89-91) head will flow the same if not more than the 190 AFR heads.

My opinion is that the size and rpm of the motor will determine the proper head to use. I needed the 210, as I have added cubes and will now be turning higher rpm with the MRII.

Hope this helps.
Aaron
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Old Jul 20, 2001 | 05:17 PM
  #42  
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Beach
I bet the gears are spinning in your head now

I will probrably invest some $$$ in my AFR210's for next winter.
Not shure on the price but the comp-port up front may be the worth wild route. If you take them out of the box (say $1500 to your door) any retidible place will want a $1000 to work them.

Hi tech is my bud the has the 86 TA. We raced last fall. I red lighted him but was a very fun race. He was running a 383 stock AFR190,230-236 hyd roller cam,3.42 gears,headers,minimram,vigilinte. and the rest of the bolt ons.
Now he ported his AFR190 to those addy specs posted above and we both went with the 236-242 solid roller from comp cams.
I have the AFR210 out of the box so in reality we are still very close. Maybe we can line up again.
Here is a pic of his car.

#2





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Old Jul 20, 2001 | 07:42 PM
  #43  
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As a side note on the AFR 210CP, I am in the process of pulling the existing engine and assembling the new engine. There is a lot of trial fit involved. The washers on the center head bolts need to be shaved at 2:30 and 9:30 on the center bolts (or you could pull the two center exhaust springs - 750# of pressure). The outer two medium length bolts need to have the washers shaved at the 9:30 position only. This only works with the 12 pt head bolts from ARP. Don't even think about 6 pt or factory style fasteners.

The factory valve cover will not suimply slide on. The area where the valve cover rail transitions from the intake area to the front/back of the head has to be filed considerably prior to installation of the cover. The breather vent has to have approx. 1/4 inch removed on the side closest to the intake. Seems the oil return area has been ramped to aid in quick oil return. Concept seems good.

The rocker stud holes actually enter the port area. These have to be sealed with liquid teflon prior to torqueing.

The valve cover hold downs are all approx. 1/4" too long. I will machine these down then run them through a die. I suppose you could use extra washers/shims. I like everything to look factory.

210 heads require 7/16" rockers at minimum (shafts optional if RPM below 7000 according to CC). Even with 7/16" ProMagnums and lash caps, the rockers and the lock nuts clear the factory vc. I was worried about that one.

Pushrods are .350" longer than early type small block Chevy ones when using SR cam. Use a pushrod checker. This is what will preclude me from starting this beast this weekend. Will have to order on Monday.

I haven't even begun with the exhaust, but I will update. Heads are great, and the reason to go with 210 vs. 220 is with 220, they require either the Jesel or TD shaft which precludes use of factory covers.

I have the Jesel shaft set-up on my 18° heads that are to go on my big motor for the other car, but that's a whole story in itself.

Just an update.

Aaron
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Old Jul 21, 2001 | 01:25 AM
  #44  
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Beach, I would take another look at the Brodix heads. I have heard from my engine builder (that has a flow bench), Brodix is the only company that is accurate with their flow # claims. All the AFR heads he has tested have been well off. I have the Brodix Track 1 heads with 2.08 / 1.60 valves, they require a 1206 intake gasket. Here are the flow #'s out of the box with NO porting:
Lift In. Ex.
.200 - 130 / 103
.300 - 178 / 142
.400 - 223 / 165
.500 - 256 / 175
.600 - 259 / 183



[This message has been edited by 396 Roadster (edited 07-21-2001).]
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Old Jul 21, 2001 | 11:06 AM
  #45  
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The numbers as I had posted prior were from testing after they had a touch up valve job performed. Cost to flow is $20, so the test is a no brainer while the machinist has the heads.

BTW, in my previous post, the AFR 210CP .600 and .650 flow numbers were moved under the AFR 190 flow numbers when the message actually posted. Judging by the actual flow numbers, the AFRs flow quite well.

Too bad I won't be able to use them anytime soon.

Aaron
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Old Jul 21, 2001 | 11:54 AM
  #46  
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AKS, thanks for the info. very useful!!!

Beach, even the SR "mucho ported" (to a 1206), it still only flowed 264cfm. So heads that can flow 300 wouldn't do much good. the key is going to be finding the best the low lift flow with the smallst runners that max around 270 or so. Unless the extrude honing can do some magic on the SR...who knows

btw, i hear a lot of people say that the AFRs don't flow anyway near advertized, but it seems to me that every time someone has real flow numbers, they do, in fact, come pretty close. Does anybody have any real evidence that AFRs don't flow as advertized?? remember flow benches vary, so you need relative flow as well. The only time i saw low flow data on the AFRs was in a comparo where ALL the heads tested flowed on the low side (my conclusion was the flow bench was calibrated on the low side). In an article in Chevy HP, they spent a lot of time setting up a new, top of the line flow bench for a comparo, and the AFRs were almost right on. The data provided by AKS and Hitech would also indicate flow that was pretty close to the numbers advertized by AFR.

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Old Jul 21, 2001 | 05:19 PM
  #47  
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What are you guys thoughts on the AFR 210CP with the MRII and a SR 236°/244° @ 0.050, 622I, 630E on a 383. Everything was set up to run on a 408, but there was a mix up. It looks as if it will be some time until the 408 will be ready, and I think I am in a position to keep the 383 (at least for the time being). The 383 has a Callies crank, Oliver forged rods (possibly billit, jury is still out), SRP pistons, and billit main caps.

The rest of the car is an '87 roadster and it has an ATI blower (10-11 # boost @6000 rpm), full roller valvetrain, 58MM, 6spd, 3.45D44, full weight, street car.

Just looking for options.

Aaron
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Old Jul 22, 2001 | 01:08 PM
  #48  
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Thanks everybody for all the great information in this thread.

I am first going to flow test and then port and flow test again the Superram intake, followed by track testing. The results should be interesting.

Then I'll move to the heads...

Cheers,
Beach Bum
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Old Jul 22, 2001 | 07:06 PM
  #49  
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Beach

That sounds like a great game plan. You should only do 1 mod at a time. This way you will be able to accurately measure the new mod.

Who is going to port the Superram , LPE, or someone else ? When are you planning to do this ? Also, are you going to flow the base with the superram ?

Vic

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Old Jul 22, 2001 | 11:17 PM
  #50  
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Vic,

Probably myself, but might have Extrude Hone eat it up a bit first and then I'll massage and match.... but not sure it.

later
Beach
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Old Jul 22, 2001 | 11:37 PM
  #51  
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Beach, let extrude hone do the final hit. they'll make it smooth as glass. have it ported or do it yourself...get it all portmatched and just a hair smaller than you want and have extrude hone take it the last few hundredths.

when do you plan to rip it apart...i know you're still in a points race.

AKS, that sounds like a great combo. Is that cam hyd?? LSA? etc??

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Old Jul 22, 2001 | 11:46 PM
  #52  
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Ralph,
The old cam in the 350 was hydraulic 112 LSA. I have a larger hydraulic roller in the '89 383. The new combo (supposed to be 408 ci) was to utilize the solid roller that I have mentioned, it to being a 112 LSA.

I don't know what I am going to do now. I will no more after visiting the machine shop, tomorrow.

Aaron
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Old Jul 23, 2001 | 10:05 AM
  #53  
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if that 236 is a solid roller, i don't think it's too big for the 383. I think Bowtye8 here is using a similar cam in his miniramed 383. It will be interesting to see how it performs with the SR.

good luck

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