Hey everyone, I have a few, very newb-ish, questions. I?m new to the world of Vettes
(and performance vehicles in general) and am trying to learn as I go along. I know that
it?s always best to learn from actually working on a vehicle with someone who knows what
they?re doing, but taking 24 credits a semester limits one?s free time. So most of what
I know has come from books. So, while I?m sure these questions seem rather silly, I?m
wondering if some (very patient) person could help me out.
1. I?m interested in what I think most people call retro-fitting, or putting newer parts
on an old car. I know that it?s possible to replace a carb system with a multi-point
injection system, but my understanding is that these still inject the fuel before the
fuel/air mixture pass into the combustion chamber. However, I know that the tech exists
to inject the fuel directly into the combustion chamber. Does anyone know if it?s
possible to retro-fit just such a system on an old carb system?
2. My next question is related: I?ve heard people around the forum talk about ?crossfire
injection.? What is this?
3. My third question has to do with retro-fitting as well. Is it possible to install
overhead cams (especially DOHC) in a system that currently has pushrods and rocker arms?
Thank you to whoever answers these; I appreciate your patience!

Welcome to the Corvette Forum.

#1. I think what you are referring to is direct injection where the fuel is injected directly in the combustion chamber a la diesels. I've been reading recently where a few mfg are starting to do exactly that with gas engines. As to retrofitting, don't know.

#2. The Crossfire system first appeared on the '82 Corvette and consisted of two throttle body injectors on a cross ram type manifold. Was also on the '84 but was replaced in '85 w/ Tuned Port Injection.

#3. Not sure about DOHC heads for the small block but they're probably out there and if so, probably someone here knows about them.

The LT5 is the only GM DOHC piece that I know of, though Lingenfelter did some work in that area as well. Nothing even close to the right vintage for a C3 though.

The LT5 is a work of art... :)

http://www.kitcarusa.com/articles/imagePage.php?imagesrc=800px-GMLT5.JPG

bill.

Found what you're looking for: http://www.cadvision.com/blanchas/54pontiac/ChevyEngines.html

Might be hard to find any of these today.

Like Bill said, the LT5 was precision piece but about the only thing it had in common w/ the SBC was bore centers.

As to the question posted: an over-head cam engine is a totally different design than an over head valve. A double over head cam allows for less valve float at higher RPM due to only having to handle ie: half the load in valve weight. They are capable ofsustaining a higher rpm and over longer periods of time.

I have seen the DOC engines used in racing. They're real pricey though, roughly 15 to 20 Gs. Hot Rod Mag had one on the cover, many years ago.

The link in my last post was the Hot Rod story and cover. Really interesting reading.

Shark,
Yes, that is super interesting, and in '71. Did these engines ever get competitive in the racing field? I suppose these engines would be for, at that time, Formula 1 cars or something like that. Being into most only drag racing in the early '70s, I never heard about this motor. There were three guys who I used to go to the track w/ who had competitive NHRA cars. As a high school kid, I learned alot from them.

Thanks for sharing the cool article.

You guys are awesome! Thanks for the reading; it was very interesting. I really appreciate the help.