Don Terrill’s Speed-Talk

I've posted about this motor before. I've been coaching a friend on this motor and i think i might get fired pretty soon because i can't figure it out. It has me looking like a fool. Its got all top notch parts and won't perform. Tell me what you think :

423 SBC 3.875 stroke x 4.165 bore dart little m block , callies crank, JE pistons (short block from steve schmidt race engines)
13 - 1 CR runs on AV gas, also tried C12 makes no difference
AFR 227 fully CNC heads with T&D shaft rockers
AFR titan plastic intake 4150 flange single plane with 1" spacer on top
QFT 1050 carb (4150 flange)
comp custom solid roller 274 / 282 @ .050 .660 lift 110 LSA installed 4 advanced.
1.75 hooker super comp headers for a G-body
3" exhaust with flowmaster super 40 mufflers.
holley 150 fuel pump / 1/2 " fuel line
78 pontiac Lemans 4.56 gear, turbo 350 / 5500 stall
around 3000 pounds race ready

if the car as a unit wont perform, id be looking into the converter. if the engine seems like a dog, id go for a different cam.

What are the times and speed at the track ? What did you expect them to be ?

there is a long story behind this motor but yesterday it went 10.6 at 124. He has data logging and with an out of the box untouched carb it was fairly rich so he went 2 jet sizes leaner front and back and gained a tenth. Since he is trying to win bracket races i don't get to tinker with stuff as much as i would like to test things. Right now i'm leaning towards convertor or maybe exhaust system.

I've never really understood what it means when i hear racers say they "blow thru the convertor". What does that feel like ? Can you notice that on data logging ?

We have a set of 1 7/8 headers to try on the car. He wants to keep running it through the mufflers but thats the first thing i would ditch.

A lot of times mufflers will just kill performance. Just today I put on my new exhaust on the car with some older slowmasters. I ran 10.92 with it last time out with walker bullets so I will see how it does with this setup. The idea is to have the new cutouts closed for a run then open them and see how much difference there is after that I will put the 3" QTP electric cutouts on so I can open them from inside the car. Willing to bet if that 10.60 is a closed exhaust run it will really wake up with those 1 7/8" headers open.

Look's like there is about 200hp missing from this combo IMO........only showing about 450hp @3000lb.

Cam has too much duration and not enough lift.

Flowmaster mufflers don't help here either.

"blow thru the converter" converter stall goes wild on launch . Converter goes into fluid cavitation and does not recover. Converter set up way too loose for the engines torque output..

Poor 60 ft and 330'
Whats ALL THE Data from a few time slips.. ?

Engine ring seal now fubared by low octane fuel use...
100LL IS not enough for near 14:1 cr..
Wrong valve springs for Comp TK lobes.

Rear facing tall cowl hood?
If a bracket racer why not a tunnel ram with 2x big eddy carbs?
About as easy simple as it gets.

What is 1/8 mph VS 1/4 mph?

True measured car weight with driver.

Do a leakdown test.

Qft "1050” carbs (4150) do not flow 1050.
Engine should have a dominator 1350 cfm on a full ported manifold... Wheres the tunnel ram.. a lot simpler.
Even for a bracket racer.

Those 227 heads are pretty shit out the box, years ago I ported a set for a guy with a 427 cube dirt late model, no word of a lie it picked up damn near 100rwhp without touching anything else.
They are small in the pinch & turbulent at high lift.
Open the pinch up to the limit of the casting & fix the turn to keep them stable.
Pull out 8 degrees of cam duration & get lift up to .700 or more & it'll be a different motor.

Tell your friend to install the 1-7/8 headers and drop the exhaust or your walking away from this . He's not helping you for being stubborn about the exhaust . The new cam went the wrong way for the combo . More duration makes more Hp but at a higher rpm . The car still has a choked exhaust. Is he still using the 9" filter you posted last year . I'm no expert or genius but my 422 combo went .3x faster in the 1/8 with 14° less cam and about 1.4 less compression and a smaller carb . With the 2.34 square.in. pinch AFR lists its not going to go faster turning more rpms . Whats the rpms it goes thru the traps at and what's the shift point . Is the chassis a limiting factor has it been fast so you know it has the capability to 60' what it needs to to go faster . There's a whole lot of things that could be holding the car back that are not just engine related . It is hard when trying to help someone that's not willing to make the changes needed and it brings your ability into question . Dan

Where’s the shift point and to what rpm does it drop down to after the shift ? And how well does it recover after the shift ?

Forget to mention the cam I'm using is a 107 lsa installed 3° to 4° advanced . Dan

I went 10.1 @132 in a 3400#.car Off the foot brake 10.9:1 comp lsm speced solid roller .650”@ 109 lsa 434 with off shelf afr235’s Combo had a lot left in it Et wise my 60ft was 1.47 solid 9 sec pump gas combo

I have seen several 414-421 sbc's dyno'd with AFR 227-235's. Best one I've seen was around 650-660...they tend to peak around 6500.

I agree on the cam being too long with not enough lift. I would want 10° less or more on the intake for sure, as much lift as you can make room for or afford. I just don't see the current cam being better anywhere than a smaller cam, within the rpm range that the heads are going to want to run in. Converter could be looser as well, although I don't think that's likely all of it.

i agree that it seems to be missing 200 hp, or at least 175. I feel quite good about the cam. A very knowledgeable friend helped me choose it and its very close to what Mike Jones suggested. I'm sure it could be slightly better with more lift but its not the source of the 200 problem. I also looked at the data logging and i think the convertor is doing what its supposed to do. He has the 2 step at 4500 rpm ( i suggested 3500 but he says it works better at 4500) its flashes to about 5700 and doesn't have any weird spikes or anything. It 60 foots in the 1.43 area if i'm not mistaken. I'll try and get more accurate info to post. Maybe the heads are a problem as a couple people have suggested ?
Brian