Inliners International Forums General Discussion Hi Performance 250 build

Hi everyone,I'm a newbie here and had a couple of questions.First off,I'm Joe,nice to meet you all! I have a Pontiac Ventura with the 250 engine,and I want to build it for street.I researched and researched on it for a year and thought I knew what I wanted to do with it.I knew first I needed to ditch the integrated intake head to do anything with it.Here's the rub.I went to buy a head from a guy in Oregon and mentioned I was looking at the Clifford dual weber 38 setup with their cam and headers,and the guy ranted for an hour about how their products are junk and I'm throwing my money away(but he'd sell me a blower setup for 7k)Anyway,I suspect there's some bad blood there somewhere,and before I dump 3k into this motor I just want some honest opinions about Clifford Performance parts.I've been familiar with them since the 70s and always thought they were well respected in the 6 banger community. Can anyone help me out here? Thanks!

Hi Joe,
Welcome to the forum.

Clifford's parts are OK, the Q.C., not so good.

If you could , tell us here what your goals are for your Ventura?

Street only car, track car, Both?

Is gas mileage a concern?

Weight of vehicle. Axle ratio. Auto trans, manual?

Every day driver, weekend car?

Best bang for your buck mods?

Turbo, blower.

Do you need to pass a smog check?

For a 4 BBl install, I like this intake, but it's pricey.
http://www.ebay.com/itm/161462168269?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I would go forced induction, if, you want to be really pleased with the output.

I tried all sorts of combination of intake manifolds & carbs., different cams,, etc, etc, was never really completely satisfied,, The Clifford side draft manifold, & 3 DCOE Webers was really good for a naturally aspirated engine, but I also had 12:1 compression.

Best intake naturally aspirated for a street car, no EFI, Side draft Webers.

The straighter the shot to the intake port is better, sharp abrupt 90 degree turns,,, not so good.



MBHD

I'd go with pretty much my exact setup: Langdon headers, 2.5" single exhaust, Offy single intake (heated) and, the one thing I'd change, a 500 cfm carb.

With the set up Im running the calculators all say about 400 cfm but I can tell it's not enough.

I didn't go with any Clifford stuff just because of the price. dollar for dollar the route I went is just better. More power earlier in the curve, plenty up top, and all really bolt-on.

You're smart to get rid of the integrated head. Not so smart tto look at dual carbs. Too much of a PITA to tune. Stick with a single. You don't really gain anything with dual other than pretty looks.

Eventually I'll go with, probably, an Isky cam and head work but I'm pretty good power wise right now.

Well,it weighs about 3200 curb weight.As for use,although I'd like to drag again like the old days,I most likely won't,lol. It's no GTO.I'm looking to get it where it can hold it's own against your average small block,has plenty of torque,a nice lope to it.I definitely want to wow factor under the hood,lol.I found it in Nichols SC in a garage where it sat since 92. 62,000 miles on it and factory paint,so I've got a clean car to start with.Really want the duals just for that "wow".I know they're hard to tune.A snail guage usually dials them in on a multi carb bike.Should work on this as well I would think.Was going with the 264 Clifford cam with hydraulics and undecided as to go with the Langdon cast headers or the Cliffords.Either one I'll have to fabricate the rest of the exhaust for.I spoke with Larry several times over the past several months and for what I want he came up with the dual 38s,264 cam kit and split headers.As for milage...eh! It's just my "take the grandson for a cruise" and maybe the wife to dinner kind of car.Not a daily driver.Mostly for show.Thanks guys....

OK,

not sure if you just want to drop in a no custom do not do modifying drop in type engine?

This would not be a drop in exchange engine, but,,I would build a 292 if you are wanting for it to keep up w/the V-8's & are naturally aspirated.

If you build a 250, you are going to need gearing, better trans,converter, etc to be really pleased with running a 250.

Cubic inches is what you would need if going N/A (Naturally aspirated)

I know EFI will chime in and offer a 4.2 trailblazer engine, but that is even more work involved over a 292 engine.

So, do you still want a standard 250 engine in their, or??

MBHD

I doubt a 292 will fit.

Eye candy?



its 200 lbs more than my Camaro. You can make it scoot and toot.

It will fit.

Same engine compartment as your Camaro, a 292 will fit in your Camaro.

MBHD

No way would a 292 fit. My 250 barely fits and it's a couple inches shorter.

maybe a side draft set up might fit but I doubt it. The problem is one of height. The 292 is 1.75" taller.

Anything will fit in anything. I helped a buddy stuff a 300 six into a Pinto.

Sure they fit. Look at how tall your engine mounts are.
They fit in a friends 65 Nova, Chevelles, El-Caminos etc.
There are different engine mounts to let the engine sit lower. Make your own also.
Easy peezy.

That's also why they make cowl induction hoods.

I can't fit my finger between my subframe and oil pan.

Could I make it fit? Probably. Would I have ground clearance after I was done? Probably not...

Most all engines have very little clearance between the subframe and oil pan, even with small blocks and big blocks.

That's done intentionally to keep the center of gravity as low as possible.

My point was that I don't think you can gain 1.75" down there by lowering the engine any.

With this set up my air cleaner rubs a little on the hood blanket.



I definitely don't have another 1.75" unless I went with side draft carbs or a lot of custom fabrication. If he wants to do that more power to him but I wanted to keep the hood stock on mine.

Full disclosure: I'm running a 1" carb spacer. Regardless I don't see how it could fit even without that.

A couple years back The 12 Port News had an article on Marv Wiegand's Austin Healy with a crossflow inline six. He built an intake manifold with runners angled downward so the carbs flowed uphill. The stock hood fit.

Once again: a LOT of fabrication.

I'm not saying it can't be done. I'm saying it can't be done easily. It's not a bolt-in thing.

It's too much for me to try when better results can be had by adding a turbo charger or nitros to the 250. Sure you can do the same to the 292 but at that point are the gains worth it?

...but if he wants to do it more power to him. I'd even lend a hand if it were local.

Well, I was curious enough if this combo would handle the "average" small block v8 that I ran it through the DeuceCoupe Gonkulator. I was surprised, low-15s and 87mph, which by 1960s-70s showroom stock standards would be average-to-good for a smallblock. Of course by the late-1980s and newer it was not so easy.

Recipe I used - 1976 (?) Ventura, 3300lb curb, T350, 3.55 posi, 2500 stall.

250-9.0cr, lump head, Clifford with twin 38 webers (about 440cfm total), Langdon exhaust in to dual 2". Clifford 264H cam set up 4 advanced, ie 110 LSA, 106 ICL.

Torq 265 at 3600
Powr 252 at 5400
2.25 60ft
9.87 at 71.1 1/8 mi
15.44 at 86.8 1/4 mi
7.33 0-60mph
As you said, not a GTO (well maybe a base powerglide GTO on a bad day?) but a fair runner. This is about the best I would expect, just so you have an idea of what the combo might do when done. I agree though about the novelty-bling factor, otherwise just toss something ordinary/boring/new under the hood.

As far as the 292 fit, yet its 1.75" taller, but fits in my 62-63 Novas just fine, I can even use a flat-base 14x2" air cleaner (but a 14x3" will hit the hood). Not sure if the 75-79 body hood is higher or lower though. That would add a lot to the swap in a heavy 3300lb car if you can find one.

DeuceCoupe,
run those same numbers but w/a 292 & see what you come up with.

Thanks

MBHD

OK same everything, just a 292 vs 250

Torq 310 at 3000
Powr 268 at 5000
(So I shifted at 5200 instead of 5600)
60lb heavier with the 292.

3.25
11.93 at 69.4
17.55 at 87.5
Cough, cough, ok that heated the tires up.
Now lets try again, same traction as the 250

2.13
9.39 at 73.5
14.82 at 89.7
That would take on some 289HiPo Mustangs.
Not quite stock L79 territory but getting there per the old road tests.

Is this with the same cam, compression, carbs ect. As the 250?

Yup, all same, just longer stroke and longer rods, and same imaginary pistons both with 9.0cr.

That's about 5 carlengths quicker in the 1/4 mile, hard to even see the other guys taillights that far ahead.

That is a considerable difference in torque between the two engines. Also note that the 292 peaks 600 rpm lower much closer to engine speeds used on the street. IMHO the 292 would be a lot more fun to drive. Does the "Deuce Coupe Gonklator" also have gas mileage figures? Jay6155

Yes, I wrote a separate program called the Gasolator for MPG.
It is pretty empirical, based on real MPG data, not EPA nonsense. I think when EPA does their city MPG, they cruise a loop with traffic from 1952, or maybe 1932 or something.

None of our new cars ever get near the EPA city number in REAL city driving, and I do know how to get good MPG.
Similarly, you have to be good AND lucky to equal the EPA highway number. I think they cruise a steady 60mph to get that one.

For a new car, look at the EPA City estimate. That is a good estimate of what your real OVERALL mileage will be. People sit in rush hour parked on the freeway thinking their truck is getting 26mpg. Its really getting less than half that. Log every tankful in your car, it is really revealing.

That said, here is what the Gasolator says about these builds:

250
MPG.....Condition
14.40.....City
16.79.....Overall
19.71.....Highway, 60mph real trip
17.83.....Highway, 70mph real trip

292
MPG.....Condition
13.52.....City
15.73.....Overall
18.42.....Highway, 60mph real trip
16.57.....Highway, 70mph real trip

Just for fun I re-did the 250build with a 200-4r trans, same 3.55 gears, no other changes
250-200.4r
MPG.....Condition
14.34.....City
19.12.....Overall
23.34.....Highway, 60mph real trip
21.45.....Highway, 70mph real trip
No diff in the city but about 3.5mpg better out on the road.
Depends how many freeway trips you plan I guess!

Thank you.
amazing what the friction increase from the longer stroke costs in gas.