Senate negotiators on economic stimulus legislation are warning their House counterparts not to plan on making many changes to their delicately crafted version of the bill.

Sen. Olympia Snowe (Maine), one of three moderate Republicans planning to support the $827 billion measure, said Monday that she doesn’t think there are any more changes that could be made to attract additional GOP votes.

Many Senate Republicans have “deep, serious concerns about what should be in the package,” Snowe said on MSNBC. For her part, Snowe said she thinks the bill strikes a good balance between tax relief and spending, although she added, “I would have preferred many of these things to be taken out, frankly.”

President Barack Obama has said he agrees with House Democratic leaders that Senate cuts to education and energy-efficient programs should be restored in the final House and Senate conference report. But Senators have signaled that adding those provisions back may kill the measure in their chamber.

“There’s always room for negotiations in a conference, but this one can’t vary too much. That’s just the reality of it,” said Sen. Joe Lieberman (ID-Conn.), one of the lead negotiators on the Senate compromise. Lieberman also was speaking on MSNBC.

Lieberman referred to Snowe and the two other Republicans supporting the bill — Sens. Arlen Specter (Pa.) and Susan Collins (Maine) — as “the heroes” who are making a stimulus bill possible.

The Senate is poised to take a key test vote Monday afternoon, and move toward a final version of its recovery package on Tuesday.

Meanwhile, House Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) signaled that House Democrats will push to restore funds for classroom construction and renewable energy investments, among other things, when the bill heads to conference committee.

“There’s a lot that we think, in the House bill, we should have in the final package,” Van Hollen said on “Fox News Sunday.”

However, House Democrats know that “this is not the time to draw any lines in the sand. I don’t think anyone’s going to say if I don’t get my way with this provision in the House bill, I’m not going to accept the package,” Van Hollen said.

Congressional leaders are still aiming to send a final bill to Obama by Friday, although Senate Majority Leader Harry Reid (D-Nev.) has threatened to keep his chamber operating through the weekend to wrap up business.

House Democrats are expected to name Appropriations Chairman David Obey (D-Wis.), Ways and Means Chairman Charlie Rangel (D-N.Y.), Education and Labor Chairman George Miller (D-Calif.), Transportation and Infrastructure Chairman James Oberstar (D-Minn.) and Budget Chairman John Spratt (D-S.C.) to sit on the conference committee.

A spokesman for House Minority Leader John Boehner (R-Ohio) said he is waiting on Democrats to announce their picks before naming his.