howdy all, ive been thinking about finally doing some performance upgrades on my stock Crossfire engine. ive been doing some research on all types of upgrades such as cams, heads, rockers etc. My question to the community is what should i tackle first that will leave me with potential for growth. would it be better to get performance rocker kit before a cam? or vice versa? if there are other ways to get performance out of my engine id gladly love to learn from all suggestions. i would also like recommendations for parts that will work greatly together. all ive been worried about while tackling performance work is product compatability and tolerance issues. i hear that alot of people have trouble with rockers and head covers so i wanna make sure to do this right and get proper parts to minimize issues. any and all suggestions and recommendations are welcome (except changing the crossfire lol)

thank you all

 

"First thing to do with potential for growth"....

What's your budget? Pretty much in order of what you'd need for future growth:
​​​​​​
EBL Flash ll ECM $1100
86pph Injectors for a 454 $100 - 150 each
Heads $1200 - 1600
Headers $$
IF you find someone willing to part with a functional Renegade intake $2k+

Just enjoying what ya got, $60 for a tank of gas

 

I recently had a similar question for my 1984. I have a separate thread that many suggestions and advices here: https://www.corvetteforum.com/forums...i-for-tbi.html.

My goal is to have budget improvements, without spending $2k for a deficit intake

 

Well, the EBL may NOT be available anymore. Dynamic EFI is stopping the install the HAM board interface to the newer ECMs. This WILL be a huge problem for the CFI community. Just letting everyone know about this, it's coming. GL All!

 

im gonna say the budget will be around 1k-3k . im planning to take it slow and buy the parts paycheck to paycheck regardless of budget. if yall have any recommendable brands or products necessary im all for it and open ears. im more worried about tollerances and compatability with cams and heads/ rocker kits so thats why i havent really purchased anything as of now. im really looking for more info of what i should be looking for when buying these types of things. thank you all for the help and suggestions!

 

the main limitation of CFI is CFM (airports). You can find cheap intake manifold for carbs with higher air flow (I took personally Performer 2101) and increase fuel delivery with a higher fuel pressure / bigger injectors.
By replacing internals you can increase the RPM, thus the max power, but the torque will remain about the same. The power is just torque x revs, thus by increasing max revs, you increase the power. But in typical conditions, you will rarely be reving engine on 7k RPM, so torque is your friend.

Another bottleneck is head ports, and low compression rate. You could spend elbow time and port the head yourself. for the compression rate, you could resurface the heads a little to increase it. All are the budget options, but would require much more hassle. There are cheap heads from Vortec engines that are compatible with our blocks. They have bigger ports, but they have different intake manifold bolting

I'm building my custom ECU block based on rusefi open-source firmware. Eventually, probably, I'll end up having a custom boxed ECU solution like EBL. But it's still a long path.

 

ive seen guys port the heads and intake and i think thats a pretty good idea. i plan to go that route for sure in the future. i think id rather stay with the crossfire if possible but just do alot of internal work. do you think itd be worth sticking with it? or would i have more potential for more power with a carb setup

 

I didn't say about carb. I was saying about carb-style manifold, that you can put TBI onto it. The main problem is with ECU. When you port your intake/heads, and replace fuel, the stock ECU wouldn't adjust to that. So you need to have a solution for tuning ECU. Stock 1984 ECU is not very tunable. You can reflash it, only buy and burn new chips. ECU is the starting point.

People go with carbs because there is no ECU, and they can physically tune the fueling. People move to TPI because there are way more options for ECUs and simple tuning. And intake manifolds.
I went hard-code path with TBI because I want to keep stock as soon as possible, and I'm interested in the building a custom ECU.

 

Hello my 2 cents...

1) mildly port your intake;
2) rebuild and upgrade your heads; Mildly ported. These would include lighter valves, that are larger, performance valve job, better seats, better head bolts, better thinner head gaskets, better springs and keepers;
3) Swap your camshaft, very mild upgraded;
4) 1.6 Full roller rockers;
5) Money allowing retro roller lifters?;
6) high performance timing Chain;
7) larger injectors and a different fuel pump;
8) open up your current TBI and clean and rebuild them;
9) a set of headers;
10) custom true dual exhaust with a crossover or X-pipe;
11) high Performance Coil, cap, rotors, wires and plugs;
12) 2,600 rpm Stall converter;
13) 3:45 or 3:55 rear gear ratio;

14) as others have said you will have to adjust your timing, your fuel pressure and if possible a cheap off the shelf computer chip. This is not ideal but staying close to stock parts with a mild upgrade together will send you close to 275 to 300 FWHP; and

15) premium synthetic fluids where every you can.

Think of it this way, with all the above you will have an increase of +75Hp at all times. Thus the equivalent of a 75hp shot of NOZ.
These will cost above $3,000, but doing as much as you can and roping in a wrenching buddy you can save a great deal.
I suggest you gather parts over time as funds allow. Buy parts you can take to an independent exhaust shop to do that work.
Find a reputable machine shop in your area and start a relationship, you may end up getting some affordable light porting should you not try to
do it yourself... If the heads are enhanced and rebuilt with premium parts you will get the benefits. The heads on you car were used from like 1978 to 1986 so finding another set that doesn't have issues may be a good option to rebuild and upgrade, just swap them out when you do the top end upgrades. Hardly anyone likes these heads so they are a dime a dozen... they made from 180hp to 230hp in stock form, they were used with carburetor, TBI and TPI setups in these vette, they ran with automatic and manual tyranny.

Just my 2 cents and a road map I would use... Remember these parts were engineered and mass produced with reasonable reliability built it. This is evidenced by the many 45 year old Corvettes and the 40 Year old ones on the road today that still have a little pep in their steps...

Hope other would fine tune this to your budget requirements. Good Luck and Cheers - Jarrod
PS. This is assuming your bottom end is in good shape, if not at least new rings and bearings and gaskets would be needed. Do a compression check, also the lower your mileage the better, once you are over 150,000 miles, definitely rebuild the short block, and open up oil passages and a proper oil pump.
Over 100,000 you are about 50/50 on reliability...

 

ive heard that if your heads are not already cracked that they are very susceptible. is it worth rebuilding them or should i just find some kind of newer style one with the upgrades you have mentioned(valves,rockers, springs, etc.)

 

You wouldn't drive a lot on a cracked head. Cracks in heads would likely make exhaust gases leak into your coolant system, thus overheats.
Once you get your head offs, it's 100% worth rebuilding them, at least checking valves for leaks. Leaky valves might cause some HP drops, but in the best case you would go back to stock 200HP

 

gotcha, thanks so much for all the wisdom and help! ill update with different parts or questions i have!!

 

Well if you already own the heads they have survived for 40 years and do not have crackers or other issues, they can be rebuilt better than stock... Everything bolts right back up no mismatch and the original numbers matching the car they came in.
So a head that ran for 8 or 9 years production run and was the only head for every single Corvette in 1982, the one 83' all 1984, 1985 and about half of the 1986 production run... Remember that the difference with these cast iron heads in the 86' was 230hp, the lighter weight 86' Aluminum heads ONLY made 5 more horsepower, thus theoretically speaking whatever horsepower improvements that can be made on the 1986, 1987 heads would be nearly identical to the 84 head. Remember every single Corvette came with these so it speaks volumes as many are still running just fine...Good Luck, the $600 to $2,600 new heads purchase is eliminated thus money to get the rest of the setup.

 

that sucks

 

wow, didnt know that piece of trivia. thanks for that info. the heads themselves can for sure stay, but would you recommend updating the innards? or do you think the upgrade would be miniscule? the only reason i brought up the heads was because ive read that others have had cracks in theirs and was worried about that. i havent examined mine to know for sure but the possibility could be there, no?

 

Port the intake then decide what you want to do. Going down the rabbit hole costs money. If when I built up my engine the prices are what they are today I'd have never done it.

 

Prices are definitely going up, I was going to send my engine out to get a quote for 383 to find out it starts at 8-k so I’m going the diy route myself by reading crossfire info but a lot base around finding a renegade which is not an option now. Port intake is pretty much only option with keeping it from what I’ve read.

 

yeah. I luckily have a bad renegade but it works. My heads alone went from ~$900 for the pair to nearly $2k. Everything has gone crazy. I could justify $2200 for everything. I can't say the same in the current market.

 

1985 fuel pump and adjust fuel pressure to 13psi
replace stock exhaust manifolds with headers and free flowing exhaust.
port intake manifold. port match head side and taper entrance is all that is needed for stock cam and heads. I would clean up the full length of runner also.
this is relatively easy. this is as far as I would go with stock heads and cam. this is relatively cheap and easy.
after this it turns into a project. just matters what you want and are willing to do

tapered entrance. side to side taper 1.1 to 1.2. top just tapered with available thickness. tapered the end of runners

head side. ended up with gasket match. this picture shows port a little smaller

manifold with rod welded to opening. a lot more work. It's not perfect, for sure. the inner 4 runners are easier to increase cfm than the outer four runners.

can't just hog out runner, because water pockets in-between 2 of the runner walls. can also get into egr passage. maxing out runner with no taper and no radius entry, will flow the same as a smaller runner with taper and radius entry. can't radius all four sides, tapering is effective, but not as good as radius.

 

WOW! Those runners look pretty familiar, why did you do that?