Considering a LT1 cam swap, will I lose low end torque?

Car is a '91 5-speed with 3.27 gear. (swapped in a 9 bolt) I autocross and street drive the car so low end and mid range is what I'm after. Gaining 20hp at 4000rpm won't help me, losing any torque under 3000rpm would be going backwards.

Exhaust is gioing to be L98 manifolds, 3 inch Y-pipe w/ single 3 inch cat and 2.75 pipe after that. Headers are not an option.

Air cleaner has tall lid and 50% larger snorkle only pulling air from the teardrop Formula hood.

I do plan to have a chip made once it's all done.

Would I be better off just getting 1.6 rockers and leaving the rest alone? Not looking to change the world, just pick up 15-20lbs of torque off the bottom. (1500-3500rpm)

 

I say If your going to be doing all that work on a cam swap, why limit yourself at just the lt1? Go big(er) while your in there

 

Start with 1.6:1 full roller rockers to reduce friction and gain valve lift and duration under the curve.

The Vortec/B-car LT1 cam is a very torquey grind, but I bet the stock peanut cam is better from off-idle through 3,500 rpm. A cylinder head change also will not help under 4,500 rpm.

Why are headers not an option? A good set of properly sized headers will easily add 20-30 ft/lbs of torque across the RPM range.

A correctly calibrated chip would definitely give you some more torque if the timing advance is properly adjusted.

 

Why no headers? I'm racing in a particular group that imposes a budget cap. Headers will push me way over what I can spend. I can get cams and so forth used for really cheap, but had little luck with good headers. I don't want long tubes.

 

Have you considered LT1 B/F car manifolds? I drilled 1 extra hole in the flange of both and put them on my old 350. Very little HP gain going with headers over LT1 manifolds on a stock engine.

 

interesting idea, but the image won't load. Do you use the 3rd or 4th gen y-pipe? Or must you bend your own?

 

I do not like the factory Y-pipes......On my Express I used the flanges from the junkyard B-car and had a shop with a mandrel bender bend my pipes to connect to the highflow cats I used.

The LT1 manifolds must have flowed pretty well for me. I made 330 RWHP through them. After I swapped from a 206/210 cam to a 215/220 cam, swapped to Edelbrock ETec 170 heads, and swapped on doug thorley headers I made 374 HP. That was only a 44 hp gain for cam, heads and headers.

 

Cheaper parts ...If you cant pick up a cheap "take out" cam $229

Melling MC1337 cam 241 245 414 428 ...1994-96 Impala SS ,Roadmaster

http://www.oreillyauto.com/site/c/de...2244&ppt=C0364

Melling MC1320 cam 241 244 414 428 ....96 TRUCK grind

 

And he will end up just like you with the "395" cam. All that work and still gutless. I couldn't stand the MC1320 grind in my Express. A production LT4 cam woke that engine up ALOT!

 

Listen to fast hes done them all .......

Production LT4 cam 253 260 446 450 115 / 1.5 RR .476/.480 at 1.6 RR

P/N 12551142

 

Funny that my old thread here popped back up when I made the new post about the heads etc.

Sootie007, I read your carb thread and you did pick up some power right? 20-30? That's all I'm really after. I got a good deal on the parts so I figured I'd go for it.

 

"Sootie007, I read your carb thread and you did pick up some power right? 20-30? That's all I'm really after. I got a good deal on the parts so I figured I'd go for it.[/QUOTE]"

Yes I picked up some power but its all midrange and nothing night and day performance wise off idle etc ....I would imagine autocrossing you want all the off idle to midrange power you can get ...

Don't forget I am carb swapped.... you are still TBI correct ? If anything being TBI - you "probably" will have more torque than me .

I suggest you listen to Fast355 and his recommendations particularly on the combo / cam he recommends . I haven't been able to find a stock "PRODUCTION" LT4 cam link for you - LT4" Hot" cams are out there in droves but the stock grind looks harder to come by ...maybe someone can suggest a source or find a link for you to buy one ......good luck and let us know how your new combo works out .