wesmigletz

We picked up an early 64 Rochester fuel injection unit this week. we are stroking the 327 with a 3.875" crank, and will top the engine with ported 461X heads. We will pick a cam after the compression is finalized. We are leaning to a 274 Comp XS solid flat tappet (already have, and it's on a reduced base circle). We are also considering a 30/30 cam if we do not need a reduced base circle cam to clear the rods. Due to the $$$ spent on the FI unit, we are probably going to forego a HR cam at this time. The crank cleared the block, but the rods will require additional clearancing. Once the rods clear, we will look into pistons.

I've been told the Rochester units can be modified to support additional HP, but do not have any experience with them myself. I would like to see pictures of the port work and other modifications done to them. Pictures of earlier FI units would also be appreciated. Additional tips would be appreciated as well. TIA, Wes

Pics
http://www.picturetrail.com/gallery/...617&uid=649897

KyleDallas

I like the specs on the 274XS.... 274int/280ex with 501in/510ex and a 110LSA...
If you can get the fuel/air to it properly with the lift/flow you have
achieved from your ported heads... I'd bet you are going to have
one of the most powerful/streetable motors on the Forum that's running
stock type equipment...

Mickey Thompson ran a 4.0 stroke crank in a 283 with some one-off
Buick rods..Speed-o-Motive offers a stroker kit with a Small Journal 3.75 crank..
Im not sure what rods they are using.

Ohio Crankshaft has small journal 6.0 length H beams...
http://www.ohiocrank.com/hbeams.html

Eagle has just started making I beams in 5.7 and 6.0 for the small
journal... I believe they came out in December.
http://www.eaglerod.com/

I'm sure there are other Fuelie experts here.. I'm no expert on
on the early GM units..... but Ron's Fuel Injection might be able to
give you some advice... or perhaps have some bigger nozzles if your
engine requires it..... they specialize in Mechanical Fuel Injection for
Drag racers... so they deal with motors with all kinds of fuel/air needs.
*
http://www.ronsfuel.com/

JohnZ

Note that the functionality of the F.I. unit is closely tied to idle vacuum characteristics - I'm sure Jerry Bramlett will chime in with his thoughts.

C64BOB

I seen a number of these modified but for the life of me I don't know who'd have pictures. Larry Park (while he was alive) was really good at this. The most critical thing, is apparently, boring out the inlet and if memory serves me well you can bore to effectively get about 850 CFM. This is not a simple bore job, however, because all the entry radii need to be re-established. I think Rudy Pretti used to do these for people on the west coast. He was in Hayward or San Leandro in northen CA. BTW I've streetable injected smallblocks run close to 120 MPH (at the drags) thru mufflers with modified injection units so clearly you can achieve 500 HP with the rochester units.

wmf62

i have seen Rochester units with 2, and even 3, air meters on them to increase air flow. unfortunately no pictures....
Bill

Critter1

The basic problem that you will have with an old Rochester FI is air flow, not fuel flow. These old units were rated at around 585 CFM and all the manifold/plenum porting in the world won't increase that number at all. The restriction, by design, is at the air meter pizometer ring/cone. Unfortunately, simply enlarging this area won't work well, especially at low and mid RPM, because a larger area reduces the vacuum signal to the fuel meter. That can be compensated for by increasing the axle/link pivot ratio but then you wind up too rich at high RPM and way too lean at low/mid RPM.

There are a few things you can do to solve most of the air/fuel delivery curve problems and increase CFM without making any permanent modifications to an original unit. I'll explain later. On my way to a local car show.

I used a 63 Rochester FI unit on a 63 Corvette vintage race car that I drove at Road America in about 1989 or 90. Car had a "potent" 355" motor and actually ran faster with the FI than it did with the 750 Holley and comp manifold that it had previously. More later.........

wmf62

Bill

Seaside63

I knew there was a reason we let you in here !!

Injected Stingray

[QUOTE=Critter1;car show.

I used a 63 Rochester FI unit on a 63 Corvette vintage race car that I drove at Road America in about 1989 or 90. Car had a "potent" 355" motor and actually ran faster with the FI than it did with the 750 Holley and comp manifold that it had previously. More later.........[/QUOTE]


I would agree with that most good running street engines will respond to longer runners before increaced CFM.

jerrybramlett

Since I don't know you at all, Wes, please don't take this personally. What you're planning to do with that FI will probably disappoint you and ruin some perfectly good parts.

Chevrolet, Bill Thomas, Smokey Yunick, and a host of others modified Rochester injection units for racing back in the fifties and sixties. They found they could improve the units performance in a high, but narrow, rpm range. Outside of that particular rpm range, however, the unit's performance was ruined.

If your kind of racing stays between 6,000 and 8,000 rpm ALL the time, you might like a modified unit on the track. But, you may have a 1,500 rpm idle and essentially zero mid-range torque.

Frankly, I wouldn't modify the unit other than to make certain the fuel pressure at the nozzles was set to match the rpm you plan to drive.

wmf62

with Jerry...
Bill

63Corvette

Contact Chris Wickersham.

john neas

Chris Wickersham of Pasadena, CA has extensive experlence with the modified Rochester FI in performance applications. He is a very active vintage racer and is the one who sorted out the dual meter set up for Rich Masons Jerry Earle SR2 car. The car ran well on the track and it also has made several road trips. One being the 2002 California Mille where the car performed well. This trip started and ended in SF,while covering 1250 miles in northern CA.
Old phone number 626-359-4498

wesmigletz

Thanks to everyone for the information. I feel fortunate to be able to tap into the experience of others on the forum.

Jerry, thank you for sharing your opinion. I'll pay attention to my fuel pressure. BTW, can you give some general guidelines as far as camshaft selection, in terms of it's effect on/compatability with the Rochester injection unit. If I remember correctly, I read somewhere that 3 inches of cranking vacuum was needed to work with the mechanical FI, but I don't remember anything about idle vacuum and it's effect.


63corvette, john neas, I've heard good things about Chris Wickersham, However, my one experience with him was that he is slower than molasses going uphill in a Canadian winter. A few years back, I came across a 1961 Rochester unit that I wanted modified for use on my 59. I was referred to Chris by more than one person. He was pleasant on the phone, and seemed very knowledgable, but in the 5 months he had my unit, he never touched it. To me, that is unacceptable. The people who spoke to me of Chris spoke very highly of him, but in my case, it didn't work out... kinda like dealing with a body shop.

While the wait for my FI unit was going on, it looked like I was going back on active duty, so I started selling off my toys, including that FI unit.

I'd like to figure out how to tune and maintain the FI unit for myself. If I can't make it work, I will probably return the egine to a carb, or swap an EFI.

Thanks again,

Wes

DZAUTO

Wes,
In addition to the email I sent to you earlier today, I also have to agree with Jerry Bramlett above. With a GOOD stock rebuild, and a good cleanup and some detailing, the FI unit that you have will make you very happy.
The 7380 units were the best and last units made.
I've thrown in a couple of pictures of my early unit, which has multiple modifications, but none of them are really obvious. Thus, for the most part (except for the chrome parts) it looks pseudo stock (which was my intent).

wesmigletz

Tom,

Thank you for posting the pics. I love the way you built your car. I think our goals for the 62 are along a similar vein.

I was looking at your pictures and realized I would need to vent the block. The 7380 unit I have has a PCV valve on the rear passenger side. Would that be connected to the vent on the rear of the block?

I saw this listed at Paragon for an early 64 (mine is dated Nov 1963)


and these were listed for 1964 - 1965


Any thoughts on this?

Thanks again,

Wes

wmf62

those will work if you have an engine block with a hole in the top rear to put them in, but if you're going to use a later block, then i suggest you vent it through the valve covers.





Bill

6T5RUSH

Wes,

I like your attempt at the stealth approach to factory components. If you're able to use the fuelie unit, it sounds like this 327 will be a screamer. Hope you're able to work the driveability issues out.

I'm curious. Those flow #s you achieved from the '461 heads are very impressive. If you are at liberty to divulge, could you put a price tag on that shops charge to get those heads to flow that way.

Here's my e-mail: jkaram@wideopenwest.com

Good luck on your endeavor here.

Jim

wesmigletz

Bill, we're using a 62 block, so we have the vent. I have a set of LT-1 valve covers like yours currently on the car. If I were to run them, it looks like it would be as simple as running a hose from the valve cover to the PCV, and a vented cap of some sort on the oil fill tube. Because of our dual MC, we cannot run an aircleaner like yours. I've considered moving our expansion tank to the pass side, like the 65 Vettes. That would free up some room. We also picked up a pair of 901/902 manifolds at Pomona on Sunday, that look like they never been installed. I may go ahead and port them, and not re-install the headers with the next engine swap, which might make things a little simpler... especially if I drop the engine down...

Jim, the heads were done by Mike Stark at CFM Performance www.cfmperformance.com . He came highly recommended by the guys at Team Chevelle. I got burned by a local guy, and former friend, on another engine build, which led me to look elsewhere. I'm sure there are a few local guys who could have done similar work, but I think I had my fill of So Cal BS... unreturned calls, grossly inflated egos, missed deadlines, way over budget, at least 4 or 5 versions of the "you get what you pay for BS", all the while they stick it to you... I have friends that had similar experiences at highly recomemneded (oft covered in the magazine shops). Also, I would generally recommend not telling anyone you pay to do work that the parts are going on a Vette.

I haven't had the heads independently flowed to verify his numbers, but his work is beautiful. Mike has been porting the camel hump heads ever since they were the darling of the roundy round guys. Expect a 5-6 week turnaround. If your heads need everything, you will be in them around $1500. The porting alone was $750 give or take. If I had any sense, I would have shelved the stocck heads and bought a set of the new AFR heads.

Wes

Russ T Gate

Wes
If a modified Rochester unit is what you want check out the Jan 07 issue of Vette magazine. Ken Adrianse wrote a artical about his blown 65 with Rochester injection. His car was also featured in Vette in Feb of 04. He worked with Craig Railsback at Blower Drive Service in SoCal who is also doing work with the Rochester units. Ken is a nice guy and I'm sure he would share his knowledge on Rochester FI, and he's right around the corner from you in Thousand Oaks.
Good luck
Russ