Will I break into the 12's

[mikemustang289]

Here is my current combo which has run a best of 14.5 @ 96 on an easy launch

68 Mustang Coupe, 289, .030 flattops, 9.1:1 CR, stock rods w/ARP, Ported Windsor D0OE, 1.85/1.55, Crane [email protected], .498/.498, RPM Intake, Longtubes, Bigs 650 DP, T5Z w/.059 OD, 9" Locker, 4.30 gears, 31 spline moser axles. full MSD.

Ok. so here is the combo I am building

306 roller, 9.2:1 CR, ARP everything, AFR 185's, Jay Allen cam: base specs: 218/224 552/541 114LSA, RPM Intake, 650DP, T5Z, 4.30 gears, 26X10.5 E.t. Streets, MSD.

Jay didn't give me full valve timing specs yet but from what he said his cam would outperform the XE274hr that I was going to run, he said it is less agressive but would increase the dynamic compression to ~165-170 psi and require 91-93 octane. I trust what he says but I was always under the impression that more power came from bigger a bigger cam.

I'm curious what you guys think my new combo will put down and how much I will gain e.t. wise. Goal starting out in this build was low-mid 12's.

it just seems hard (for me) to believe that I'll knock 2 second off my e.t. from 17 cubes, smaller cam, and better heads. The general perception I get from others is that going from 289-302 won't gain me much, a lot of people keep asking why I didn't go with something bigger, but I think their idea is that bigger is better. Just curious what you guys think?

 

[Clienterror]

I could see a low/mid 13...MAYBE high 12's

To be honest I'm supprised your old set up only got you a 14.5.

 

[mikemustang289]

I could see a low/mid 13...MAYBE high 12's

To be honest I'm supprised your old set up only got you a 14.5.

The car has too much gear for the 289, it stops pulling in 4th before I finish due either to the cam, wrong springs, or just the efficiency of the heads. All of the 4 times I did run it, it ran at 96 MPH, with practice the e.t. would drop (higher launch, burnout) but I don't see MPH increasing with that setup.

Jays cam will make power to 6100 and rev cleanly to 6500 so valve floating or head restrictions won't be an issue. Gearing should not be a problem either as the 306 will only be pushing 5800-5900 if I trap around 105mph.

There are a few other small mods I plan to do before I take it back to the track; drag shocks, battery to trunk, and a line lock so I can get a decent burnout.

car should weigh 3100 or so, no PS, PB, AC, and I'll lose around 50 pounds going to the aluminum heads.

 

[Clienterror]

Then I could see it being possible bro, I'm sure once you make a few passes on it you can break into 12's. Just gotta remember its a totally diff engine so you kinda have to relearn it

 

[rd]

What you have should work. My 82, at 2900lbs, gets into the 12's with less stuff. The 96 mph shows that you have a good bit of et left on the table.

You need launch. What are your sixty foots?

My 82 does this with a 68 302 block, 78 rods and crank, iron GT40 heads off of a Lightning truck, and a C4/10 in converter, and 4.10 gears. With 275-50-15 BFG Drag radials. It traps 103 to 106 or so. Seems to be right where I calculated it, at +/- 6000 rpm. The 430 is a bit steep, but should be ok.

One big change I made was from home ported D80E heads, with the 70cc chambers to the Gt40's. That is worth a good bit.

With your combo, I would work on the 60 fts some, sticky tires, etc.

Then spray it! All the times above are on motor, but it runs high 7's in the eight on the bottle easily.

 

[Redrooster]

If you get that combo right it should run low 12s. I have a friend that has a 93 hatch that runs 12.40s on street tires (not e.t. streets) on a 306 w/ afr 185s. Its a EFI motor with a healthy cam and a performer RPM intake. Traps about 111mph.