[AJ-]

I have a Ventura with 400 in it. The bottom end was basically a stock rebuild as I acquired it (cast silvo-lite pistons and stock reconditioned rods) and the heads are 6x heads that have been milled a bit and ported some. The static compression ratio is 8.5:1. The cam specs are 213/218 @0.050 with around .451/.468 lift with 1.65 roller rockers factored in. 114 lobe separation. The trans is a th350 with shift kit and stock converter, rear gears are 3.42 with TruTrac. Exhaust is stock manifolds with 2.25 dual exhaust. Stock original leaf springs and I ran it with 26x8.5 et drags.

I took it to the track last summer and managed to get it down to a 13.92 @ 96.8mph. 60’ was 1.99s. Does this sound like I’m pretty close to my potential with this combo? What would be my next step to get quicker? Update the rear suspension? Would headers be worth it? I’m pretty happy with how it runs on the street and the results at the track but if I’m wondering if I’m leaving anything on the table that would be worth doing.

[slowbird]

No you should have lots left. We ran 13.8s with a Ventura and the original 350 with 120,000 miles on it.

[ta man]

Exhaust and different torque convertor would help

[steve25]

First off is this combo going to spend most of its time running the 1/4 mile, or on the street?

[Stan Weiss]

Originally Posted by AJ-

I have a Ventura with 400 in it. The bottom end was basically a stock rebuild as I acquired it (cast silvo-lite pistons and stock reconditioned rods) and the heads are 6x heads that have been milled a bit and ported some. The static compression ratio is 8.5:1. The cam specs are 213/218 @0.050 with around .451/.468 lift with 1.65 roller rockers factored in. 114 lobe separation. The trans is a th350 with shift kit and stock converter, rear gears are 3.42 with TruTrac. Exhaust is stock manifolds with 2.25 dual exhaust. Stock original leaf springs and I ran it with 26x8.5 et drags.

I took it to the track last summer and managed to get it down to a 13.92 @ 96.8mph. 60’ was 1.99s. Does this sound like I’m pretty close to my potential with this combo? What would be my next step to get quicker? Update the rear suspension? Would headers be worth it? I’m pretty happy with how it runs on the street and the results at the track but if I’m wondering if I’m leaving anything on the table that would be worth doing.

Can you post a full time slip. The 1/4 et and MPH along with your 60' times seem to indicate to me you that there is not much left unless you find more power.

Stan

[Stan Weiss]

Originally Posted by slowbird

No you should have lots left. We ran 13.8s with a Ventura and the original 350 with 120,000 miles on it.

Brian,
Do you remember what your MPH was?

Stan

[Formulas]

Originally Posted by Stan Weiss

Brian,
Do you remember what your MPH was?

Stan

96.8 as stated

[prostreet64]

Short of tearing into the engine I would say headers with 2&1/2" pipes and free flowing mufflers will help some. Also a better converter to get your 60' down a little which will benefit the entire run. You didn't mention what carb you are using or the fuel system in general. There might be some gain right there. Also, timing and shift points might help, but you may have already played around with those variables. Sounds like a decent 1/4 mile time for what you have to work with. Good luck.

[Tim Corcoran]

Sounds like your doing pretty good already why mess with it. For more power you could mill the heads to get more compression at least 9.25 to 9.5 max. Make sure you mill an equal amount off the intake side also. Then you will need to get shorter push rods and an adjustable valve train if it's not already. As already mentioned upgrading the exhaust to 2-1/2 pipes is a good improvement headers will give you a few ponys but do you really want to mess with headers? Of course a mild converter will also improves your 60' times but do you really want to put a high stall converter on a street car. With regards to maximizing a combo it's usually not one thing but a combination of many. It's a big expense to add the things to maximize your performance and sometimes it's a never ending process chasing more power. it's your dollars

[78w72]

Originally Posted by Formulas

96.8 as stated

Hes asking a different person, the OP's MPH was 96.8...

[slowbird]

Originally Posted by Stan Weiss

Brian,
Do you remember what your MPH was?

Stan

Sorry no I don't, this was in 98-99 too long ago for me to remember lol

[PAUL K]

Originally Posted by slowbird

Sorry no I don't, this was in 98-99 too long ago for me to remember lol

Look at your log book

[AJ-]

Thank-you for the responses. I’m not looking to go back into the engine, just wondering if there are tweaks around the edges that could have some benefit or if I should call it good. Other tuning notes include 36 degrees timing all in and I’ve got the curve dialed in as per recommended by Cliff R in a previous post when I was setting it all up. I’m currently running a Holley 750 with vacuum secondaries (stock jetting) and that is what I ran the 13.9 with. I have not played with the spring rate so maybe that’s something to try. I do have a Qjet but it will need some work to make it happy at idle/off idle.

The car is a summer driven street car. The track time is just to get it dialed in as well as check my improvements over the original stock drivetrain (15.6s) to feel like it was all worth it 😊. I figured I would post my results and see if it sounds like I’m close to where I should be based on the engine specs or if I should chase it harder. I’ve considered headers and converter but not sure it would be worth it or not at this point. For a couple tenths not worth it but if it’s more significant maybe that’s next.

Full time slip:
60’ = 1.99
330’=5.74
1/8 = 8.86
1/8 mph = 78.49
1000’ = 11.59
¼ = 13.92
¼ mph = 96.80

[slowbird]

Originally Posted by PAUL K

Look at your log book

Sadly they've been through away, lots of really good notes and testing gone

[android 211]

Check part numbers but Firebird headers often fit Venturas. I put Hooker headers on a 68 Firebird without lifting the engine. I did remove the starter and the oil filter mount to get them in. I also had to raise the front of the car off the ground a lot. Mine was a 350 and the headers were 1 3/4", it gave it a great rush at 3000 rpm which was a lot of fun. My cam was more mild, the '067'. So yeah, it will pull a lot harder at the top half of the rpm range and get better mileage.

[steve25]

How are you running that Holley 750 VS on the stock intake?

[Skip Fix]

I think looking at exhaust and for sure convertor. I made a run with a similar 400 Ho manifolds Summit 2801, 2.5 mandrel system but has dual cats(they were doing sniffer test back then and would not pass idle) in the 81 TA and the stock convertor was so tight it could not spin the tires-older BFGsand only ran in the mid 14s-but freaking Texas 100 degree DAP event. New convertor made a world of difference.

My first E head roller motor I ran the HO intake with a Brad Urban prepped Qjet and at the track swapped with a square bore to Q jet adpater picked up .3 with a Demon 850! SO adpaters don;t kill that much

[AJ-]

Originally Posted by steve25

How are you running that Holley 750 VS on the stock intake?

It's on an edelbrock performer intake with small spacer.

[hurryinhoosier62]

Distributor recurved? 1.5 or 1.65 rocker arms? A old friend of mine’s ‘68 Chevelle with a large journal 327 was posting 7.75s in the eighth. It was still very streetable.

[chiphead]

More intake, camshaft and converter. My old combo was a 8.7:1 400, dished pistons, RPM intake, Q-jet, mild ported 670 heads, XE274 cam, Continental 10" converter, TH350 and 3.90s. Hooker SCs and 3" exhaust. I did have to go with an electric pump and regulator to keep the Q-jet wet. It idled at about 10-12" vacuum, barely enough to run the power brakes.

Best time N/A was 13.0 at 104 MPH, shifting at 5500. 60 foots in the 1.8x range with 255 ET streets. Best time on a 100 shot was 11.70s at 112MPH. It had forged internals and liked the spray.