Don Terrill’s Speed-Talk

Done up plenty of that type of project for customers.

With the 4.030" bore and the 3.250 stroke... getting a better cylinder head on there is a great idea.

Proven Recipe:
AFR 195 Cylinder Heads - They come with the better 8019 spring and 7/16" rocker studs.
Mild hydraulic roller camshaft with a set of Morel street series lifters.
Edelbrock RPM Air Gap or Weiand Stealth if you have hood clearance issues.

BobbyB wrote: ↑Wed Jun 17, 2020 3:25 pm

ustahava67 wrote: ↑Wed Jun 17, 2020 2:53 pm It isn't a HP number that will kill a stock block necessarily.... It could be RPM or a bad tune.... I have built a few turbo SBF, 302's with 500 RWHP. They have been alive for years. My personal 347 NA I have 10 plus years bracket racing it. It still has the same head gaskets from when I put it together. My own self imposed limits are 6500 rpm and a well balanced assembly. My engine will make power to 7400 but I don't take it that high. I bracket race.... a few hundredth's ain't worth it

What is your total timing? What heads?

I run 34 total locked. Vic jr's with a offshore funnel web HR shelf cam Comp XFI. 10.8 measured static. The car runs 10.9o's in the heat at 2500 actual elevation

F-BIRD'88 wrote: ↑Wed Jun 17, 2020 10:16 pm OP What does the car run now et mph and 60 ft now.
and what does it weight race ready with u in it.?

Don't have any ET info. Weight is 3150 including driver

blackford wrote: ↑Thu Jun 18, 2020 2:09 pm

F-BIRD'88 wrote: ↑Wed Jun 17, 2020 10:16 pm OP What does the car run now et mph and 60 ft now.
and what does it weight race ready with u in it.?

Don't have any ET info. Weight is 3150 including driver

What rear suspension are you using?

Of course, not all engine builders are of the same caliber but, for those that believe that 500 HP isn't possible with 260 cfm heads, you need to go back to Mummert's thread on his EMC, 295 Ci, 289. His heads are only 235 cfm. There is no better documentation that that.

viewtopic.php?f=1&t=58737

It's a long thread but, pay attention not to just what Geoff says but, also the other builders in the thread, such as Bill C.

BobbyB wrote: ↑Thu Jun 18, 2020 2:21 pm

blackford wrote: ↑Thu Jun 18, 2020 2:09 pm

F-BIRD'88 wrote: ↑Wed Jun 17, 2020 10:16 pm OP What does the car run now et mph and 60 ft now.
and what does it weight race ready with u in it.?

Don't have any ET info. Weight is 3150 including driver

What rear suspension are you using?

4.5 leaf mid eye springs and KYB GR2 shocks. Also have under-rider traction bars that eliminated wheel hop. I just lowered the rear another 1/2" to be even with the front height. Front just got coil overs and wilwood 13" disc brakes. I may go to a 3-4 link setup someday in the back.

If you add 50 hp to your current hp the car will go about 5 mph faster 1/4 mile.. The ET will drop +/- .5 seconds.
+/-

blackford wrote: ↑Thu Jun 18, 2020 3:03 pm

BobbyB wrote: ↑Thu Jun 18, 2020 2:21 pm

blackford wrote: ↑Thu Jun 18, 2020 2:09 pm

Don't have any ET info. Weight is 3150 including driver

What rear suspension are you using?

4.5 leaf mid eye springs and KYB GR2 shocks. Also have under-rider traction bars that eliminated wheel hop. I just lowered the rear another 1/2" to be even with the front height. Front just got coil overs and wilwood 13" disc brakes. I may go to a 3-4 link setup someday in the back.

Are those Mayer springs? Did you have wheel hop with those springs before the under ride bars? Does your corvette have much better traction from a stop on the street without traction control on compared to the mustang? What tires are on your mustang?

For what its worth, I recently built a 347 with 10.4 to 1, AFR 165s (older, 1.94" valves by me, not a good as the renegades, peak flow is about 250 cfm). I would buy a bigger head I were you and buying new. I did a 3 link in mine and really like it. 63 comet, c4 auto, 3.55 to 1, 8.8, 235-50-15 r888 tires. Traction limited.

BobbyB wrote: ↑Thu Jun 18, 2020 4:59 pm

blackford wrote: ↑Thu Jun 18, 2020 3:03 pm

BobbyB wrote: ↑Thu Jun 18, 2020 2:21 pm

What rear suspension are you using?

4.5 leaf mid eye springs and KYB GR2 shocks. Also have under-rider traction bars that eliminated wheel hop. I just lowered the rear another 1/2" to be even with the front height. Front just got coil overs and wilwood 13" disc brakes. I may go to a 3-4 link setup someday in the back.

Are those Mayer springs? Did you have wheel hop with those springs before the under ride bars? Does your corvette have much better traction from a stop on the street without traction control on compared to the mustang? What tires are on your mustang?

For what its worth, I recently built a 347 with 10.4 to 1, AFR 165s (older, 1.94" valves by me, not a good as the renegades, peak flow is about 250 cfm). I would buy a bigger head I were you and buying new. I did a 3 link in mine and really like it. 63 comet, c4 auto, 3.55 to 1, 8.8, 235-50-15 r888 tires. Traction limited.

Mustang Plus springs. Always had under-rider bars on the car so never drove it without them. The corvette does have better traction even with traction control off, but then again it has 335s on the back. The Mustang has 255 Nitto NT05 tires...the largest that will fit without tubbing. I made the front suspension with fully adjustable UCAs and LCAs and was able to adjust the suspension to add caster and get the front tires away from the front fender lips. Afterwards I was able to go from 225s that rubbed sometimes to 255s that don't rub. 255s now on all 4 corners and lowered almost 2 inches. Better front suspension geometry too.

I'd skip the Morel's and run a set ig Hy-lift Johnson Full Travel lifters.

EDC wrote: ↑Thu Jun 18, 2020 8:55 am Done up plenty of that type of project for customers.

With the 4.030" bore and the 3.250 stroke... getting a better cylinder head on there is a great idea.

Proven Recipe:
AFR 195 Cylinder Heads - They come with the better 8019 spring and 7/16" rocker studs.
Mild hydraulic roller camshaft with a set of Morel street series lifters.
Edelbrock RPM Air Gap or Weiand Stealth if you have hood clearance issues.

Ok. sounds like new heads and a custom cam would get me where I want to be. I'd like to stick with a SFT.

EDC, would an RPM Air gap work up to 7000? It would be nice to go back to a dual plane and still be able to have 7000 rpm of usable rpm range. The single plane makes the car buck at low speeds and low rpm. A dual plane, new heads and a custom cam would probably have better street manners and 50+ more HP.

The carb and the ignition curve likely need work.
On a single plane , often a plenum divider really helps low rpm drivability.. May not be a full height divider but that is where to start.

If you choose to go with the SFT, .875 high lift rate cam, you have to take more precautions on break in. Low spring rates, under 300 lb, for the usual 2500 rpm / 20-25 min and highest zppd oil for at least the first oil change. They recommend more oil to the lifter/cam area but, I'm not sure that is necessary.

Low speed drivability.. If you have eliminated the pcv valve it throws off the carb calibration.. Right in the area it matters

If you are using higher ratio rockers AND you set the valve lash much tighter than cam card this increases valve seat to seat duration and valve overlap...
Effects low speed drivability.

F-BIRD'88 wrote: ↑Thu Jun 18, 2020 6:32 pm Low speed drivability.. If you have eliminated the pcv valve it throws off the carb calibration.. Right in the area it matters

If you are using higher ratio rockers AND you set the valve lash much tighter than cam card this increases valve seat to seat duration and valve overlap...
Effects low speed drivability.

Yes, especially tightening the lash. Tony Denesenko (Moneymaker Racing) told me years ago that the cam i'm using was designed for a Chevy dia lifter and that I could run the Comp 282S much tighter than .022 on a SBF. I set it to .015 which is the setting where you get advertised duration (236@.050) according to the Comp Lobe catalog.