Please help me to choose properly the camshaft


1991 L98 automatic 2.59 rear end

I already bought some parts

Mods

Trans and rear end

1.-2200 stall converter (bought it, not installed)
2.- 3.07 rear end (bought it, not installed)
3.- transgo (bought it, not installed) and oil cooler
4.- beam plates (bought it, not installed)
5.- speedo gears, red,green 92 sensor for 3.07 (bought it, not installed)
6- nitto treadwear 100 installed

engine

1.- Long tube headers installed
2.- no cats, doublé 2 1/4 exhaust to borla mufflers installed
3.- 3 wire heated 02sensor installed
4.- 1.6 rr self align installed
5.- stock L98 aluminum heads and stock 48mm throttlebody
6.- edelbrock ported base manifold (bought it, not installed)last purchased ítem


7.- lt4 springs (bought it, not installed)
8.- 30 lb injectors (bought it, not installed), I red that 24 is enough but pcmforless suggested 30lb
9.- walbro 255 fuel pump (bought it, not installed)
10.- k&n,cutted airlid,adjustable fuel pressure regulator installed
11.- msd 6al installed
12.- moates apu1 for fine tuning installed
13.-pcmforless chip not boughted until buy cam (baseline)
14.- egr, frisbie,airpump deleted


originally I wanted 180cc afr heads,268xfi cam and superram but im out of funds for this Project then I want to use the parts that I already have it.

superram difficult to found and expensive, then probably I will buy slp runners (ported)

heads, I will use stock heads unported,unmachined then .525 of lift is the limit, (maybe one day , I will (afr 180cc)

cam options: I want to use my 1.6rr

1.-lt4 hotcam with 1.6rr
24502586 218/228 .492/.492 .525/.525 112deg
probably to much for stock heads ,tpi, 3.07 gears
I red that valves float with lt4 spring then I will need other springs

2.- comp 264hr12 with 1.6rr
08-302-8 210/220 .480/.480 .512/.512 112deg
looks like a good cam for torque from 1500 to 5400
this cam with 1.6rr is like the comp 8-304-8 266 cam with 1.5rr


3.- cam suggestion ?, any advice ?

 

with what you have bought, the weak link in my humble opinion would be the heads, cam, and intake/TB. I would recommend a Comp's cam #276hr-14 Hydraulic roller lifter cam with a 58 mm throttle body, AFR 195 street heads, and a nice super ram or First intake. The 30 lb. injectors will go with this set up. The cam is very well mannered for street with a 114LSA. The lift and duration @ 50 is 220 X230 X 510 X510. it is the most cam for a near stock torque converter. I run the above set up in my 89 with a .355 rear end, headers, beefed 700 R-4 trans, a 2200 stall converter, and MT street radials when I race it. It runs 8 flat in the 1/8 mile at 87- 88 mph and will just dip into the 11's at the quarter mile when I do my part. I also converted the MAF to a MAP sensor system and had a good dyno tune. You'll be very pleased.

 

I'm using the Scoggin-Dickey LT-4 reproduction cam. It's .480 lift with 1.5 rockers, 203/211 @ .050" on 115 separation. Idles great, pulls great all over the place and revs very well with the rest of my mods. It's also something like $230.

Just my opinion, but it's a great running cam that's not expensive and will still sound stock. Great throttle response and great idle.

 

If you don't want to pocket port those 113s I strongly suggest a 3-angle or 5-angle valve job. If you can afford it, 2.00"/1.56" performance valves.

 

I agree with the above, the heads are the weak link..I have basically the same set up as you except Im running a set of "Dart Pro 1 -180 heads". Along with those heads Im running a "Erson custom grind 218/226-112 cam..This cam is very close in specs to the LT-4 hotcam and it works great with my setup...Unless your going with different heads and intake a bigger cam then this will not do much more for you.....WW

 

thanks for your answers

then, I don´t receive any benefit if I replace all this parts with a 264 cam over a stock engine ?

ported intake, cam, chip dont have anykind of gain ?

I need to replace or modify my heads

Im not sure if I remember correctly, the zz4 engine is almost like the L98 with other cam and carb and have 350 hp.
with all this parts, is not posible to reach 300hp ?

 

I have the Comp Cam 08-501-8 and it didn't mess with my ECM at all. Runs strong and I gained about 20-30HP. Ported my exhaust a little bit and gasket matched my stock heads. Budget dictated my decision to keep it minimal. I am over 300HP and that is good enough for a C4 daily driver. If I want more I will buy a C5 Z06 and save all the damn trouble guess work head aches ! Stock is the way to go and stay within factory specs and avoid the unknown. I am sure many will disagree but its my opinion. If I could go back and do it over I would have a C5 right now and not have dumped all that money into a 1988 C4. The only plus is that I have a zero mile motor and will run for many years trouble free.

 

Ok.

I cant change the heads a this moment, probably I will but not now
I want to use all the parts that I bought until this moment

I will use stock L98 alum heads (113), with out valve job, without port job, only I will replace the springs to can handle .525 of lift if is necesary (cam)
I already bought lt4 spring but I can buy other springs like beehive

I already have edelbrock base tpi stage 4 ported, probably I will buy edelbrock or slp siamese runners, and I want to sent it to ported and reduce the runner lenght to can reach 5500 5600 rpm.

with all this parts my problem is the max lift with this heads to handle a good cam that is.525
I want to use my 16rr,

please help me to choose a cam, what is your advice for cam

I saw several tpi engines with lt4 hotcam and stock heads

my option are this cams but if you have another cam in mind, please let me know

1.-lt4 hotcam with 1.6rr
24502586 218/228 .492/.492 .525/.525 112deg
probably to much for stock heads ,tpi, 3.07 gears
I red that valves float with lt4 spring then I will need other springs

2.- comp 264hr12 with 1.6rr
08-302-8 210/220 .480/.480 .512/.512 112deg
looks like a good cam for torque from 1500 to 5400
this cam with 1.6rr is like the comp 8-304-8 266 cam with 1.5rr

 

I can't say enough Comp Cam 08-501-8

 

With your rearend gear the 2nd cam is what you want


Those slps , dont fall prey to a gigantor opening port job thats just the entry way. The key is getting 100% way through the whole runner.
Im not saying this is in your plans but if it were me Id carefully slice those suckers in half then port them thoroughly weld them back up.

Lots do tons of siamesing for an impressive size opening and as you see the short turn coming up they are barely scratched up as its hard to get to. Not much real gain. They are a pain lol.

unles its a superram I wont touch a long runner without cutting them up its just not worth the hassle

 

I used the Edelbrock 3860 and SLP runners. Gasket matched the 3860 and ported big time on the SLP runners. I really drove it for the first time last night. Also have the cam I keep yelling about ! No tune or chip and it hit 90mph and stayed there never going over 3200rpm. Had I really gotten on it I am sure it will hit 160mph. We all know going beyond the stock setup costs money. Also lots of headaches. But the reward is there just waiting. I swear its not the same car anymore. It is down right fun to drive and I am not afraid of being blown away by a Toyota Camry.

 

With a 2200 stall and 3.07 gear, I dont think there is going to be a big difference in how those cams perform in in the car.

The valve float problems you read about with the hot cam and LT4 springs is nothing to worry about.... TPI is going to be 1000 to 1500 rpm short of the LTX intakes power top end wher a very few folks are having those problems.

I'd say buy the cam you can get the best deal on.
Will

 

I am in the same boat. I have a hot lt4 cam to put in but don't want to touch the heads at this stage but can not find a definitive answer if the valve springs will work without binding with the 0.525 lift. My calculation is an extra 0.070" of lift over what I have at present. Does anyone know for certain?

 

What valve springs?

Biggest problem on L98 heads is the guide/seal to retainer clearance.
Will

 

Apart from the 1.6 roller rockers the heads are stock. Just started today to disassemble so when I get the covers off I will get in with some feelers. The car is just for super street drag racing. Have done one season with EFI and am changing to Carb. Best et 13.58, mph 100.8.

 

Seems like carbed engines need more overlap. Wouldn't you want to be running something with 106-108 degree LSA?

I don't know jack about carb cams...but do know less overlap (more separation) is typical AND desired with FI engines. IIRC, the overlap helps "pull" fuel thru the carb. With FI, that's unnecessary...and somewhat less desireable -- maybe when emissions are considered.

Or maybe just the higher "dilution" of exhaust fumes from the overlap makes it harder for the O2 to do it's job correctly?

Kind of asking the general community on this one.

 

I did a 383 with new heads but my cam is the Comp Cams CL08-466-8 268XFI HR13. I went with 1.5RR instead of 1.6 due to some fears about clearance.

But if you like that old school thump this cam does it for a TPI setup. I am very pleased with it, but it might not be right for you.

Best of luck....

 

OK now you have wondering, I don't know enough about this sort of thing, will look for more information and advice. I just have the hot lt4 cam available to me and thought it would be a good option. Checked my valve springs and they are not a problem, have plenty more lift available but can't see the the stem to retainer gap.

 

Carb can be used with about any cam its just a matter of tuning. Little/lots of overlap lsa doesnt matter. EFI seems to be more picky so you see more EFI specific grinds.

 

Just get LT4 hotcam spring kit they are cheap and desined for that cam. They are also a drop in. Make sure you measure for push rod size and get the correct ones.